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System and surroundings - class-XI

Description: system and surroundings
Number of Questions: 97
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Tags: chemical thermodynamics chemistry thermodynamics
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In a closed system :

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. energy is not exchanged

  2. matter is exchanged

  3. energy is only exchanged

  4. energy and matter are exchanged

Show answer
Correct Option: C
Explanation:

In a closed system Matter is not exchanged but Energy is exchanged.

So option c is correct

Which of the following is a state function ?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $q\times w$

  2. $q+w$

  3. $\dfrac{q^2}{w^2}$

  4. $\sqrt{qw}$

Show answer
Correct Option: B
Explanation:

Solution:- (B) $q + w$

From first law of thermodynamics,
$\Delta{U} = q + w$
As we know that $\Delta{U}$ is a state function, thus we can say that $q + w$ is a state function.

The following two equilibria exist simultaneously in a closed vessel :
$PCI _5(g) \rightleftharpoons PCI _3(g) + Cl _2(g)$
$COCI _2(g) \rightleftharpoons CO (g) + CI _2 (g)$
If some CO is added into the vessel, then after the equlibrium is attained again, concertration of ?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $PCI _5$ will increase

  2. $PCI _5$ will decrease

  3. $PCI _5$ will remain unaffected

  4. $CI _2$ will increase

Show answer
Correct Option: C
Explanation:

Given reactions are,

$PCl _5 \rightleftharpoons PCl _3+Cl _2$
$COCl _2\rightleftharpoons CO _{(g)}+Cl _2$
If some $CO$ is added into the vessel, the concentration of $PCl _5$ will remain unaffected, because $CO$ reacts with $Cl _2$ and forms $COCl _2$, not going to effect the concentration of $PCl _5$ .

Bond dissociation enthalphies of ${ H } _{ 2 }\left( g \right) $ and ${ N } _{ 2\left( g \right)  }$ are enthalpy of formation of $N{ H } _{ 3 }\left( g \right) $ is $-46 kJ mol^{-1}$. What is enthalpy of atomization of $N{ H } _{ 3 }\left( g \right) $?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $390.3 kJ mol^{-1}$

  2. $1170.9kJ mol^{-1}$

  3. $590 kJ mol^{-1}$

  4. $720 kJ mol^{-1}$

Show answer
Correct Option: B

Identify the 'State function' among the following

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. q

  2. q $\times$ W

  3. q/W

  4. q + W

Show answer
Correct Option: D
Explanation:

Both work and heat are path functions. Their values depends on the path chosen to reach a particular state.
However, the change in internal energy which is equal to the sum of heat and work, is a state function. Its value is independent of  the path chosen to reach a particular state.

Which is not a state function ?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Internal energy

  2. Entropy

  3. Work

  4. Enthalpy

Show answer
Correct Option: C
Explanation:

Heat and work are not state functions. Work can't be a state function because it is proportional to the distance an object is moved, which depends on the path used to go from the initial to the final state.

An isolated system is one which neither shows an exchange of _nor _with surroundings.

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. heat, mass

  2. heat, temperature

  3. temperature, mass

  4. None of these

Show answer
Correct Option: A
Explanation:
Heat, mass

In physical science, an isolated system is either 

(1) a thermodynamic system which is completely enclosed by walls through which can pass neither matter nor energy, though they can move around inside it; or 

(2) a physical system so far removed from others that it does not interact with them.

Hence, option A is correct.

Which one of the following systems is an example of a closed system?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Some amount of water in equilibrium with its vapour in a closed and insulated vessel

  2. Some amount of hot water enclosed in a closed container which is not insulated

  3. Hot water contained in an open vessel

  4. None of the above

Show answer
Correct Option: B
Explanation:

When some amount of water is in equilibrium with its vapour in a closed but non insulated vessel, then it will be an example of closed system.

Which of the following is not a state function?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. U

  2. P

  3. V

  4. q

Show answer
Correct Option: D
Explanation:

State variables : To define a thermodynamics states of a system, we have to specify the values of certain mesurable quantities. These are called thermodynamic  variable or state variable. 
A system can be completely defined by four variables namely pressure, temperature, volume and composition. A system is said to be in a certain definite state when all of its properties have definite value. 
Between two fixed state the change in the value of state function is same irrespective of the path connection two states. 
Differential of a state function  integerated over a cyclic path returns zero. 
In other words summation of change in state function in a cyclic process is equal to zero.
Example : T, V, P and U (internal energy), H (enthalpy), S are state variables.

Warming ammonium chloride with sodium hydroxide in a test tube is an example of:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. closed system

  2. isolated system

  3. open system

  4. none of these

Show answer
Correct Option: C
Explanation:

When we are warming ammonium chloride with sodium hydroxide in a test tube, there is exchange of heat as well as mass between system and surrounding. Mass is transferred from the open end of the test tube due to evaporation. Also heat is being exchanged through the walls of test tube.

Which of the following is not a state function?


a. $U + PV$      b. $q + w$     c. $\cfrac { q _ {rev} }{ T }$       d. $q$

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. a

  2. b

  3. c

  4. d

Show answer
Correct Option: D
Explanation:

State variables : To define a thermodynamics states of a system, we have to specify the values of certain mesurable quantities. These are called thermodynamic  variable or state variable.
A system can be completely defined by four variables namely pressure, temperature, volume and composition. A system is said to be in a certain definite state when all of its properties have definite value.
Between two fixed state the change in the value of state function is same irrespective of the path connection two states.
Differential of a state function  integerated over a cyclic path returns zero.
In other words summation of change in state function in a cyclic process is equal to zero.
Example : T, V, P and U (internal energy), H (enthalpy), S are state variables.

Which of the following is not a state function?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Temperature

  2. Density

  3. Work

  4. Volume

Show answer
Correct Option: C
Explanation:

Work is not a state function. Work is a path function. Work depends on the distance or path followed by an object.

Thus option C is the correct answer.

When you combust $100.0\ g$ of propane at $500.K$ and $1.00\ atm$ in a closed container, you expected to collect $279\ L$ of carbon dioxide. Instead, when you collect the gas, it measures $651\ L$ in total.
Why have you collected more than your predicted, theoretical yield?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. The theoretical yield was calculated incorrectly.

  2. The graduated cylinder used to collect the gas was read incorrectly.

  3. You did not account for the surrounding volume of air.

  4. You did not account for the volume of water vapor that was produced.

Show answer
Correct Option: A
Explanation:

$\text{The theoretical yield was calculaterd incorrectly.}$

For a reaction to be spontaneous in neither direction, which of the following is/are correct regarding the closed system?
(1) ${ \left( \Delta { G } \right)  } _{ T,P }=0$
(2)${ \left( \Delta { G } \right)  } _{ T,P }< 0$
(3) ${ \left( \Delta { G } \right)  } _{ U,V }=0$
(4) ${ \left( \Delta { G } \right)  } _{ U,V }>0$
Codes:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. 1,2,3 are correct

  2. 1 and 2 are correct

  3. 2 and 4 are correct

  4. 1 and 3 are correct

Show answer
Correct Option: D
Explanation:

$\text{For spontaneous in neither direction:}$

(1) ${ \left( \Delta { G } \right)  } _{ T,P }=0$
(3) ${ \left( \Delta { G } \right)  } _{ U,V }=0$
$\text{is correct.}$

Select the state functions among the following:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. temperature

  2. entropy

  3. work

  4. enthalpy

Show answer
Correct Option: A,B,D
Explanation:

State function is defined as a system that depends upon the initial and final positions,

so temperature , entropy and enthalpy depends upon the initial and final state, so they are state function but work depends upon the area of PV curve.

A system where there is exchange of energy but not of mass is called _________ system.

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. insulated

  2. isolated

  3. open

  4. closed

Show answer
Correct Option: D
Explanation:

In thermodynamics, a closed system can exchange energy (as heat or work) but not matter, with its surroundings. An isolated system cannot exchange any heat, work, or matter with the surroundings, while an open system can exchange energy and matter.

Temperatures of two hot bodies $B _{1}$ and $B _{2}$ are $100^{\circ}C$ and $80^{\circ}C$ respectively. The temperature of surrounding is $40^{\circ}C$. At $t = 0$, the ratio of rates of cooling of the two bodies (liquid) $R _{1} : R _{2}$ will be:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $3 : 2$

  2. $5 : 4$

  3. $2 : 1$

  4. $4 : 5$

Show answer
Correct Option: A
Explanation:

Rate of cooling=$\cfrac { dQ }{ dt } \propto \quad \Delta T$ 

$\therefore \cfrac { { R } _{ 1 } }{ { R } _{ 2 } } =\cfrac { { \Delta T } _{ 1 } }{ { \Delta T } _{ 2 } } =\cfrac { 100-40 }{ 80-40 } =\cfrac { 60 }{ 40 } =\cfrac { 3 }{ 2 } $

Universe is :

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Closed system

  2. Open system

  3. Receiving constant supply of energy.

  4. Dissipating energy continuously.

Show answer
Correct Option: A
Explanation:

A closed system is one which can only exchange energy. The entire universe is an isolated system because it has no surrounding. Hence it is a closed system.

In a closed insulator container, a liquid is stirred with a paddle to increase the temperature. Which of the following is true?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $\triangle U=w\neq O,q=O$

  2. $\triangle U=w=q\neq O$

  3. $\triangle U=O,w=q\neq O$

  4. $w=O,\triangle U=q\neq O$

Show answer
Correct Option: A
Explanation:

A closed insulated container, a liquid is stirred with a paddle to increase the temperature, therefore it behave as adiabatic system, $q=0$

$\Delta U=q+w$
$\implies \Delta U=w\neq 0$

For an isolated system, the entropy:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Either increases or remains constant

  2. Either decreases or remains constant

  3. Can never decrease

  4. Can never increase

Show answer
Correct Option: A
Explanation:

The second law of thermodynamics states that the entropy of an isolated system never decreases, because isolated systems always evolve toward thermodynamic equilibrium, a state with maximum entropy.

Equal masses of hydrogen gas and oxygen gas are placed in a closed container at a pressure of $3.4 atm$. The contribution of hydrogen gas to the total pressure is:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $1.7 atm$

  2. $0.2 atm$

  3. $3.2 atm$

  4. $3.02 atm$

Show answer
Correct Option: C
Explanation:

Let mass of hydrogen and oxygen be $100g$

$n 1=$ no of moles of hydrogen=$\cfrac {100}{2}=50$
$n _2=$ no of moles of oxygen=\cfrac {100}{32}=3.125$
Contribution of hydrogen to the total pressure means, mole fraction of hydrogen present in the mixture (partial pressure of $H_2$)
$X_4=\cfrac {n{H_2}}{n_{H_2}+n_{O_2}}=\cfrac {50}{50+3.125}=0.94$
Contribution of hydroegn to the total pressure= $0.94\times P=0.94 \times 3.4=3.2$ atm

An ideal gas is allowed to expand both reversibly and irreversibly in an isolated system. If $T _i$ is the initial temperature and $T _f$ is the final temperature , which of the following is correct?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $T _f>T _i$ for reversible process but $T _f=T _i$ for irreversible process

  2. $(T _f)rev=(T _f)irrev$

  3. $T _f=T _i$ for both reversible and irreversible process

  4. $(T _i)irrev>(T _f)rev$

Show answer
Correct Option: D
Explanation:

$\triangle Q=\triangle U+ \triangle W$


Isolated system- adiabatic $\Rightarrow \triangle Q=0$


$0=\triangle U+ \triangle W$

$\Rightarrow \triangle W=- \triangle U$

For expansion, $\triangle W$ is positive and $\triangle U$ is negative.
This means $T _f<T _i$

Under which of the following conditions is the relation,
$\triangle H=\triangle U+P\triangle V$ valid for a closed system?
chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Constant pressure

  2. Constant temperature

  3. Constant temperature and pressure

  4. Constant temperature, pressure and composition

Show answer
Correct Option: A
Explanation:

$\Delta H=\Delta U+\Delta(PV)$

$\implies \Delta H=\Delta U+P\Delta V+V\Delta P$
In constant pressure/ Isobasic process
$\implies \Delta H=\Delta U+P\Delta V$

In which case mean free path is not affected? 

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. ${ H } _{ 2 }$ gas at$ { 100 }^{ 0 }C$ and $1 \ atm $ is transferred into a vessel at $ { 50 }^{ 0 }C$ and $0.5 \ atm$

  2. ${ O } _{ 2 }$ gas at $200 K$ and $2 \ atm$ is transferred into a vessel at $400 K$ and $1\ atm $

  3. ${ O } _{ 2 }$ gas is replaced by ${ H } _{ 2 }$ gas keeping other variables constant

  4. Medium is made more viscous

Show answer
Correct Option: A
Explanation:
${ H } _{ 2 }$ gas at ${ 100 }^{ 0 }C$ and $1atm$ is transferred into a vessel at ${ 50 }^{ 0 }C$ and $0.5atm$.
in this case $\dfrac { P }{ T } =$ constant.
In this case mean free path not affected.

A well stoppered thermoflask contains some ice cubes. This is an example of:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. closed system

  2. open system

  3. isolated system

  4. non-thermodynamic system

Show answer
Correct Option: A

When a volatile liquid is introduced into an evacuated closed vessel at a particular temperature, both evaporation and condensation take place simultaneously. The system reaches equilibrium state when:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. the liquid is completely transformed into the corresponding vapour

  2. equal amounts of liquid and vapour are present in the system

  3. the rate of evaporation becomes equal to the rate of condensation

  4. liquid cannot be converted into vapour and vice versa.

Show answer
Correct Option: C
Explanation:
Solution:- (C) The rate of evaporation becomes equal to the rate of condensation
As we know that the equilibrium in a system is established when rate of forward reaction is equal to the rate of backward reaction.
Hence the rate of evaporation becomes equal to the rate of condensation.

Both q and w are ______ function and $q+w$ is a ______ function.

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. state, state

  2. state, path

  3. path, state

  4. path, path

Show answer
Correct Option: C
Explanation:

Answer $C: $Path, state.

The change in energy of a system is equal to the difference between the heat added to the system and the work done by the system.
$\triangle E=Q-W$ ($W$ is $-ve$, if work done on system)
$Q$ and $W$ are path dependent, but $\triangle E$ depends only on the state of the system and not how the system got to that state.

A well stoppered thermos flask contains some ice cubes. This is an example of:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. closed system

  2. open system

  3. isolated system

  4. non-thermodynamic system

Show answer
Correct Option: C
Explanation:

An isolated system is a thermodynamic system that can not exchange either energy or matter outside the boundaries of the system.

Thus, a well stopped thermos flask containing ice an example for isolated system.

Which of the following is a path function?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Internal Energy

  2. Enthalpy

  3. Work

  4. All of the above

Show answer
Correct Option: C
Explanation:
Path functions are properties or quantities whose values depend on the transition of a system from the initial state to the final state. The two most common path functions are heat and work

A physical quantity is said to be state function if its value depends only upon the state of the system and does not depend upon the path by which this state has been attained. E.g pressure, volume, temperature

Which of the following statement is false?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Work is a state function.

  2. Temperature is a state function.

  3. Change of state is completely defined when initial and final states are specified.

  4. Work appears at the boundary of the system.

Show answer
Correct Option: A
Explanation:

Work is not a state function. It is path function. Its value depends on the path chosen to reach a particular state.

Which of the following are state property?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Internal energy (U)

  2. Volume (V)

  3. Heat (q)

  4. Enthalpy (H)

Show answer
Correct Option: A,B,D
Explanation:

Internal energy, volume and enthalpy are state properties. Their values are independent of  the path chosen to reach a particular state.
Heat is a path function. Its value depends on the path chosen to reach a particular state.

Identify the state quantity among the following

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. q

  2. q-w

  3. q+w

  4. q/w

Show answer
Correct Option: B,C
Explanation:

Both work and heat are path functions. Their values depends on the path chosen to reach a particular state.
However, the change in internal energy is equal to the sum of heat and work. It is a state function. Its value is independent of  the path chosen to reach a particular state.

Identify the state functions.

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $S$

  2. $q$

  3. $w$

  4. $q+w$

Show answer
Correct Option: A,D
Explanation:

Both work and heat are path functions. Their values depends on the path chosen to reach a particular state.
However, the change in internal energy is equal to the sum of heat and work. It is a state function. Its value is independent of  the path chosen to reach a particular state.
Entropy is a state function.  Its value is independent of  the path chosen to reach a particular state.

An open system can exchange both matter and energy with surroundings.
chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

An open system can exchange both matter and energy with surroundings. For example hot tea placed in an open cup constitutes an open system.

A closed vessel contains equal number of oxygen and hydrogen molecules at a total pressure of 740 mm. If oxygen is removed from the system, the pressure -

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Becomes half of 740 mm.

  2. Remains unchanged

  3. Becomes 1/9th of 740 mm.

  4. Becomes double 740 mm.

Show answer
Correct Option: A
A closed system shows exchange of mass and not energy with surroundings.
chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

A closed system can exchange energy with surroundings. It cannot exchange mass with surroundings. For example, hot tea placed in a cup which is covered with saucer constitutes a closed system.

Which are extensive properties?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $V$ and $E$

  2. $V$ and $T$

  3. $V$ and $Cp$

  4. $P$ and $T$

Show answer
Correct Option: A
Explanation:
An extensive property is a property that depends on the amount of matter in a sample. Mass and volume are examples of extensive properties.
Volume and energy both depends on amount of substance.

Hence, the correct option is $A$

Which thermodynamic parameter is not a state function ?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. q at constant pressure

  2. q at constant volume

  3. W at adiabatic

  4. W at isothermal

Show answer
Correct Option: D
Explanation:

$W$ and $q$ are not state functions

$H$ and $U$ are state functions
$\Delta H = \Delta U + \Delta PV$

At constant pressure, $\Delta H = \Delta U + P\Delta V$   $\Delta P = 0$   $\Delta H = q _p$

At constant volume, $\Delta H = \Delta U + V \Delta P$   $\Delta V = 0$   $\Delta U = q _v$

So, the first two options are state function.
$\Delta U = q - W$     $(\because q = 0)$    $[ \therefore$ Adialentic process$]$

$\Delta U = -W$  (state function)
Work done in isotheromal process is not a state
function
$W = -q  (\because \Delta T = 0, q \neq 0)$
$\therefore$ option D is correct.

Which of the following is path function? 


A. $W$
B. $Q$
C. $\Delta G$
D. $\Delta H$

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. A and D

  2. A and B

  3. A, B and D

  4. A, C and D

Show answer
Correct Option: B

Identify the state functions from the following:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. heat

  2. work

  3. enthalpy

  4. none of the above

Show answer
Correct Option: C
Explanation:
Enthalpy is a state function. Its value depends on the current state of the system and is independent of the path followed to reach that state. Mass, temperature, pressure and volume are also state functions. Heat and work are path functions.

Among the following, the state functions are:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Internal energy

  2. Irreversible expansion work

  3. Reversible expansion work

  4. Molar enthalpy

Show answer
Correct Option: A,D
Explanation:
State function is a quantity in thermodynamics, such as entropy or enthalpy, that has a unique value for each given state of a system. 
(or) 
A State Function is a thermodynamic quantity whose value depends only on the state at the moment, i. e., the temperature, pressure, volume, etc The value of a state function is independent of the history of the system's internal energy. Molar enthalpy and entropy are state quantities because they describe quantitatively an equilibrium state of a thermodynamic, irrespective of how the system arrived in that state.

Hence options A & D are correct.

A closed vessel contains equal number of nitrogen and oxygen molecules at a pressure of P mm. If nitrogen is removed from the system, then the pressure will be?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. P

  2. $2P$

  3. $P/2$

  4. $P^2$

Show answer
Correct Option: C
Explanation:

$\dfrac{p _1}{n _1}=\dfrac{p _2}{n _2}$ (As molecules of $N _2=$ molecules $O _2$)
($\therefore$ Moles $N _2=$moles $O _2$)
As $N _2$ molecules removed$=$ moles become half
$\dfrac{p _1}{1}=\dfrac{p _2}{1/2}$
$p=\dfrac{1}{2}p _1$
$\therefore$ Pressure reduced to half
$\therefore$ Answer is option C.

If a closed system has adiabatic boundaries, then atleast one boundary must be:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. permeable

  2. imaginary

  3. movable

  4. fixed

Show answer
Correct Option: C
Explanation:
Adiabatic boundaries mean there is no heat that is evolved or no heat exchange possible through it.

So, our system is closed that means matter cannot be exchanged but heat exchange can happen.

As here all the boundaries are adiabatic so to remain system closed at least one boundary should be movable to that heat exchange can take place.

Option C is correct.

Which of the following statement is correct?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Heat is thermodynamic property of system.

  2. Work is thermodynamic property of system.

  3. Work done by a conservative force is path function.

  4. Heat involved in chemical reaction is path independent physical quantity.

Show answer
Correct Option: D
Explanation:
Heat and work are not thermodynamic properties and work done is independent of the object's path in a conservative force.

So, a,b,c are incorrect

A heat involved in the chemical reaction is path independent which is correct (from Hess's law)

Option D is correct.

The open system(s) is/are which

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. can exchange matter with the surroundings

  2. can exchange energy with the surroundings

  3. can exchange both matter and energy with the surroundings

  4. cannot exchange either matter or energy with the surroundings

Show answer
Correct Option: A,B,C
Explanation:

Types of system : 
(i)Closed system : A system which can exchange only energy with surrounding. 
(ii)Open system : A system which can exchange both energy and matter with surrounding. 
(iii)Isolated system : A system which cannot exchange matter or energy with surrounding.

The enthalpy change for a reaction does not depend upon the:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. physical states of reactants and products

  2. use of different reactants for the same product

  3. nature of intermediate reaction steps

  4. difference in initial or final temperature of involved substances

Show answer
Correct Option: C
Explanation:

$\triangle H$ depends on :

  • Physical states of reactant and product.
  • Use of different reactants for the same product.
  • Difference in initial or final temperature of involved substances.
It is independent of nature of intermediate reaction steps because it is a path independent & is a state function.

The change in enthalpy, $\Delta H$ accompanying a process depends on the path followed.
chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

The change in enthalpy, $\Delta H$ accompanying a process does not depends on the path followed.
This is because the enthalpy of a reaction is a state function and its value depends on the inital and final states only.

State whether the given statement is true or false:

Enthalpy change is dependent on temperature and on the path adopted.
chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

State variables : To define a thermodynamics states of a system, we have to specify the values of certain mesurable quantities. These are called thermodynamic  variable or state variable. A system can be completely defined by four variables namely pressure, temperature, volume and composition. A system is said to be in a certain definite state when all of its properties have definite value.. Between two fixed state the change in the value of state function is same irrespective of the path connection two states.

Example : T, V, P and U (internal energy), H (enthalpy) are state variables.
As enthalpy is state variable so it will depend upon temperature only, not on path.

A system which cannot exchange matter and energy with the surroundings called isolated.

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. True

  2. False

  3. Ambiguous

  4. None of these

Show answer
Correct Option: A
Explanation:

A system which  cannot exchange matter and energy with the surroundings called isolated system.
A liquid in a sealed thermos flask and ice in a thermos flask are examples of isolated systems.

Which one of the following quantity is dependent on path?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Molar internal energy

  2. Volume

  3. W

  4. Q+W

Show answer
Correct Option: C
Explanation:

Work is a path dependent quantity. It is known as a path function.

1 : $\Delta U$ is state function.

2: Heat and work are not state functions.

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $\text {only 1 is true}$

  2. $\text {only 2 is true}$

  3. $\text {both are true}$

  4. $\text {none of the above}$

Show answer
Correct Option: C
Explanation:

$\Delta U$ and heat are state functions. Their values depends only on the state of the system and are independent of the path followed. Work is a path function. Its value depends on the path followed .

Like $U$ and $H, S$ is also a state function.

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

As we know,

Between two fixed state the change in the value of state function is same irrespective of the path connection two states.  Differential of a state function  integerated over a cyclic path returns zero. In other words summation of change in state function in a cyclic process is equal to zero. Example : T, V, P and U (internal energy), H (enthalpy) are state variables.

Internal energy change in a cyclic process is zero.
chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

The given statement is true.
 Internal energy change in a cyclic process is zero.
Internal energy is a state function. It depends only upon the initial and final states of the system and is independent of the path followed. Hence, for a cyclic process, the initial and final value of the internal energy is same.

Which of the following is a path function?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. internal energy

  2. enthalpy

  3. work

  4. entropy

Show answer
Correct Option: C
Explanation:

Path functions are properties or quantities whose values depends on the transaction of a system from the initial state to the final state. The two most common path functions are heat and work.

Choose the correct answer. 

A thermodynamic state function is a quantity : 

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. used to determine heat chages

  2. whose value is independent of path

  3. used to determine pressure volume work

  4. whose value depends on temperature only

Show answer
Correct Option: B
Explanation:

A thermodynamic state function is a quantity whose value is independent of path. Thus, enthalpy is a state function.
Its value depends on iniital and final states and is independatn of path followed.

Among the following, the state function are

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. internal energy

  2. molar enthalpy

  3. reversible expansion work

  4. irreversible expansion work

Show answer
Correct Option: A,B
Explanation:

State functions are path Independent

For example: $E$ (Internal energy), Molar enthalpy, entropy etc.

Why are state functions important in chemistry?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. They appear a lot in thermochemistry and thermodynamics

  2. Many equations include properties that are state functions

  3. We only need to know the final and initial states

  4. They simplify our calculations

  5. All answers are correct

Show answer
Correct Option: C
Explanation:
State functions help us simplify our calculations and see the change in value between the final and starting position, also known as a state change. Mass, pressure, density, energy, temperature, volume, enthalpy, entropy, Gibbs free energy and chemical composition are all examples of state functions in thermochemistry
In simple words, the state functions are important in chemistry as we only need to know the final and initial states.

Hence, the correct option is $C$

Which statement is correct?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. The final destination is not important with state functions

  2. The change in altitude was the same for the train and the hikers, therefore the change in altitude is a state function

  3. The starting point is not important with state functions

  4. The hikers put more effort into climbing therefore the change in altitude is not a state function

  5. None of these
Show answer
Correct Option: B
Explanation:

The statement B is correct.
The change in altitude was the same for the train and the hikers, therefore the change in altitude is a state function. The value of state function depend only on initial and final value and is independent of the path followed.

Which statement BEST describes why work is a path function

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. You finish at a different place

  2. You start at a different place

  3. The amount of work varies depending on which path you take to get to the destination

  4. The amount of work is the same whichever path you take to get to the destination

  5. Work is not a path function, it is a state function

Show answer
Correct Option: C
Explanation:

The statement (C) BEST describes why work is a path function.
The amount of work varies depending on which path you take to get to the destination.
State function is independent of the pah followed whereas path function is dependent on path followed.

Consider the following reaction, taking place in a container fitted with a movable piston.
$2SO _{2}(g) + O _{2}(g) \rightarrow 2SO _{3}(g)$
Suppose we place two moles each of $SO _{2}$ and $O _{2}$ in the reaction vessel at $25^{\circ}C$, and adjust the volume to give a total pressure of $1.0\ atm$. The reaction is ignited by a spark, and goes to completion. The temperature is returned to $25^{\circ}$.
Which of the following best describes this system after reaction is complete?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $SO _{2}$ is limiting. The volume of the system remains the same.

  2. Neither reactant is limiting. The volume of the system decreases.

  3. $SO _{2}$ is limiting. The volume of the system decreases.

  4. $O _{2}$ is limiting. The volume of the system remains the same.

Show answer
Correct Option: A

Which describes an endothermic reaction?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Positive $\displaystyle \Delta H$

  2. Negative $\displaystyle \Delta H$

  3. Positive $\displaystyle \Delta G$

  4. Negative $\displaystyle \Delta G$

  5. Positive $\displaystyle \Delta S$

Show answer
Correct Option: A
Explanation:

The term endothermic process describes a process or reaction in which the system absorbs energy from its surroundings so enthalpy change should be positive

Which of the following statements are correct?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $\Delta H$ is a state function

  2. Value of $\Delta H $ is independent of path taken

  3. $\Delta H$ can be determined under standard condition

  4. All of the above

Show answer
Correct Option: D
Explanation:

Change in enthalpy $\triangle H$ is a state function as its value doesn't depend on the path taken i.e. they give a unique value for each given state of a system. Since it gives value independent of path taken, its value at standard condition can be determined(25℃ and 1atm)
Hence all statements are correct.

Which of the following statements are not true?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Heat is a macroscopic physical property

  2. Heat is an intrinsic property of a body

  3. Heat is stored in a body as internal energy

  4. Heat is path independent

Show answer
Correct Option: B,D
Explanation:

An intrinsic property is a property of a system or of a material itself or within. It is independent of how much of the material is present and is independent of the form of the material. Heat flow is a results of a temperature difference between two bodies hence, it is not an intrinsic property of substance.

Two important examples of a path function are heat and work. These two functions are dependent on how the thermodynamic system changes from the initial state to final state.

Which of the following functions are path independent?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Work

  2. Heat

  3. Gravitational potential energy

  4. Internal energy

Show answer
Correct Option: C,D
Explanation:

In thermodynamics, a state function or function of state is a function defined for a system relating several state variables or state quantities that depends only on the current equilibrium state of the system. State functions do not depend on the path by which the system arrived at its present state. A state function describes the equilibrium state of a system.

For example, internal energy, enthalpy, Gravitational potential energy and entropy are state quantities because they describe quantitatively an equilibrium state of a thermodynamic system, irrespective of how the system arrived in that state.

Which of the following is path function?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Work

  2. Specific volume

  3. Pressure

  4. Temperature

Show answer
Correct Option: A
Explanation:

In thermodynamics, a state function or function of state is a function defined for a system relating several state variables or state quantities that depends only on the current equilibrium state of the system. State functions do not depend on the path by which the system arrived at its present state. A state function describes the equilibrium state of a system.

Hence, work is a path function and not state function.

An isolated system is that system in which:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. there is no exchange of energy with the surroundings

  2. there is exchange of mass and energy with the surroundings

  3. there is no exchange of energy and mass with the surroundings

  4. there is exchange of energy and mass with the surroundings

Show answer
Correct Option: C
Explanation:

An isolated system is a thermodynamic system that cannot exchange either energy or matter (mass) outside the boundaries of the system. An isolated system differs from a closed system by the transfer of energy. Closed systems are only closed to matter, energy can be exchanged across the system's boundaries.
Hence, correct answer is option C. 

Steady state is represented by :

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Getting raw materials.

  2. Intake of food and energy.

  3. Intake of materials and energy, elimination of wastes and dissipation of energy.

  4. Removal of waste products and intake of raw materials.

Show answer
Correct Option: C
Explanation:
Living beings require energy for their day to day activity. They generally consume food for intake of energy. They generally consume food for intake of energy, The utilize energy and eliminate the rest of the waste.
In the whole process, there is no change in energy and mass. Hence it can be considered as a steady state.
To get clear understanding of steady state read the following example:
When the drain of bathtub is open and water is being added into the bathtub at same rate, then the amount of water in the bathtub is constant.
Water draining=Water added
It is a steady state as the state variable volume is constant overtime.

Which of the following state function not zero at standard state?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Enthalpy

  2. Entropy

  3. Free energy

  4. None of the above

Show answer
Correct Option: B,C
Explanation:

Solution:- (B) entropy and (C) free energy

Entropy and free energy are the state function which are not zero at standard state.

Work is __________ function.

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. path

  2. state 

  3. both path and state

  4. none of these

Show answer
Correct Option: A
Explanation:

Work is a path function and not a state function. The amount of work done is different for different paths although the initial and final states are the same. The amount of work depends on the path connecting the initial and final states.

Which of the following is/are not state function?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $q$

  2. $q-w$

  3. $\cfrac { q }{ w } $

  4. $q+w$

Show answer
Correct Option: A,B,C

A system absorbs 186 kJ of heat and the surroundings do 120 kJ of work on the system. What is the change in internal energy of the system? Express the internal energy in kilojoules to three significant figures.

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $440KJ$

  2. $360KJ$

  3. $120.32J$

  4. $-200J$

Show answer
Correct Option: B

The work done in an open vessel at $300$K, when $112g$ iron reacts with dilute $HCl$ to give $FeCl _2$, is nearly:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $1.1$ kcal

  2. $0.6$ kcal

  3. $0.3$ kcal

  4. $0.2$ kcal

Show answer
Correct Option: A
Explanation:
The reaction involved is:
$Fe+2HCl \rightarrow FeCl _2+H _2$
Atomic mass of $Fe=56 g/mol $
Thus, 56 g of Iron reacts with 2 moles of HCl to give one mole of Hydrogen gas.
Initial volume of $H _2$ gas = $V _1 = 0$
Final volume of $H _2$ gas=$ V _2$
Using ideal gas law:$PV = n R T$
where n=mass/molar mass, R=8314 J/K/mol and given that T=300 K
$PV _2 = (112/56) \times 8.314 \times 300 = 4988.4J$
Work done $= -P \Delta V=-P(V _2 - V _1) =-P V _2 = -4988.4J$
negative work done is work of expansion.
since 4184 J=1 kcal
thus $4988.4 J=1.19 kcal$ of work is done by the system.

An open vessel at $27^{\circ}C$ is heated until ($\tfrac 25$)th of the air in it has been expelled. Assuming that the volume of the vessel remains constant. Which of the following option is correct?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Final temperature is 500 K

  2. Final volume is 2 times the initial volume

  3. Final pressure is 1 atm

  4. None of the above

Show answer
Correct Option: A
Explanation:

$T _{1}=27°C=27+273=300 K$


Let $n _{1}$ be n.

$n _{2}=n-\cfrac{2n}{5}=\cfrac{3n}{5}$

$T _{2}$=?

We know that, $n _{1}T _{1}=n _{2}T _{2}$

$\Longrightarrow n\times 300=\cfrac { 3n }{ 5 } \times { T } _{ 2 } \ \Longrightarrow { T } _{ 2 }=500K=500-273=227°C$

An open vessel containing air is heated from 300 K to 400 K. The fraction of air originally present which goes out of it is:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. 3/4

  2. 1/4

  3. 2/3

  4. 1/8

Show answer
Correct Option: B
Explanation:
 
According to ideal gas equation
$PV = nRT$
$\Rightarrow \; n \propto \cfrac{1}{T}$
$\Rightarrow \; \cfrac{{n} _{1}}{{n} _{2}} = \cfrac{{T} _{2}}{{T} _{1}}$
Given that:-
${n} _{1} = 1$ 
${T} _{1} = 300K$, 
${T} _{2} = 400K$ 
${n} _{2} = ?$
$\therefore \; \cfrac{1}{{n} _{2}} = \cfrac{400}{300}$
${n} _{2} = \cfrac{3}{4}$
The fraction of air present in the vessel after heating ${n} _{2} = \cfrac{3}{4}$
The fraction of air which goes out of the vessel $= 1 - \cfrac{3}{4} = \cfrac{1}{4}$

System in which there is no exchange of matter, work or energy from surroundings is:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. closed

  2. adiabatic

  3. isolated

  4. isothermal

Show answer
Correct Option: C
Explanation:

Closed System - The system in which only energy can be exchanged with the surrounding.


Adiabatic - The process in which heat is not exchanged by the system with the surroundings, i.e., $Q=0$.


Isolated - The system in which neither energy nor matter can be exchanged with the surroundings.  

Isothermal - The temperature remains constant, i.e., $\Delta T=0$.


Hence, the correct answer is option $\text{C}$.

In a closed system : $A\left( s \right) \rightleftharpoons 2B\left( g \right) +3C\left( g \right) $ if the partial pressure C is of doubled then partial pressure B wil be:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Twice the original pressure

  2. Half of its original pressure

  3. $\dfrac { 1 }{ 2\sqrt { 2 } } $ times, the original pressure

  4. $2\sqrt { 2 } $ times its original pressure

Show answer
Correct Option: C
Explanation:
Solution:- (C) $\cfrac{1}{2 \sqrt{2}}$ times, the original pressure
${A} _{\left( s \right)} \rightleftharpoons 2 {B} _{\left( g \right)} + 3 {C} _{\left( g \right)}$
${K} _{P} = {\left( {P} _{B} \right)}^{2} {\left( {P} _{C} \right)}^{3} ..... \left( 1 \right)$
If we double the partial pressure of $C$, i.e., ${P} _{C}' = 2 {P} _{C}$
$\therefore {K} _{P}' = {\left( {P} _{B}' \right)}^{2} {\left( {P} _{C}' \right)}^{3}$
$\Rightarrow {K} _{P}' = {\left( {P} _{B}' \right)}^{2} {\left( 2 {P} _{C} \right)}^{3}$
$\Rightarrow {K} _{P}' = 8 {\left( {P} _{B}' \right)}^{2} {\left( {P} _{C} \right)}^{3}$
Since ${K} _{P}$ is constant,
$\therefore {K} _{P} = {K} _{P}'$
$\Rightarrow {\left( {P} _{B} \right)}^{2} {\left( {P} _{C} \right)}^{3} = 8 {\left( {P} _{B}' \right)}^{2} {\left( {P} _{C} \right)}^{3}$
$\Rightarrow {P} _{B}' = \sqrt{\cfrac{{P} _{B}}{8}}$
$\Rightarrow {P} _{B}' = \cfrac{{P} _{B}}{2 \sqrt{2}}$
Hence the partial pressure of $B$ will be $\cfrac{1}{2 \sqrt{2}}$ times of its original pressure.

Which of the following statement is correct?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. The presence of reaction species in a covered beaker is an example of open system.

  2. There is an exchange of energy as well as matter between the system and the surroundings in a closed system.

  3. The presence of reactants in a closed vessel made up of copper is an example of a closed system.

  4. The presence of reactants in a thermos flask or any other closed insulated vessel is an example of a closed system.

Show answer
Correct Option: C
Explanation:

In a closed system (For example, the presence of reactants in a closed vessel made of conducting material e.g copper) there is no exchange of matter, but exchange of energy is possible between system and the surroundings.

The state of gas can be described by quoting the relationship between_____________.

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. pressure, volume, temperature

  2. temperature, amount, pressure

  3. amount, volume, temperature

  4. pressure, volume, temperature, amount

Show answer
Correct Option: D
Explanation:

The pressure $(P)$, volume $(V)$, temperature $(T)$, amount $(n)$ etc. are the state variables or state functions.

Select incorrect statement(s):

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. A closed system with all adiabatic boundaries must be an isolated system

  2. Total heat exchange in a cyclic process may be zero

  3. Entropy of a closed system is maximum at equilibrium

  4. Molar gibb's Energy is an extensive property

Show answer
Correct Option: A
Explanation:
Since heat is energy, only two systems can stop it from crossing the boundary closed and isolated system. So yes, adiabatic process can happen in an isolated system. But all adiabatic process need not happen in an isolated system, it can happen in a closed system also.

Two closed vessel $A$ and $B$ of equal volume of $8.21L$ are connected by a narrow tube of negligible volume with open valve. The left hand side container id found to contain $3\ mole \, CO _2$ and $2\ mole$ of $He$ at $400K$. What is the partial pressure of $He$ in vessel $B$ at $500K$?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. 2.4 atm

  2. 8 atm

  3. 12 atm

  4. None of these

Show answer
Correct Option: B
Explanation:

partial pressure of $He$ in vessel $B$, 

$PV = nRT$
$P _{He} = \dfrac{nRT}{V} = \dfrac{2\times 8.314\times 400}{8.21} =8atm$

Ammonium carbamate dissociates as ${ NH } _{ 2 }COON{ H } _{ 4\left( s \right)  }\leftrightharpoons 2N{ H } _{ 3\left( g \right)  }+{ CO } _{ 2\left( g \right)  }$. In a closed vessel containing ammonium carbamate in equilibrium, ammonia is added such that the partial pressure of ${ NH } _{ 3 }$ now equals to the original total pressure. The ratio of total pressure now to the original pressure is :

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $\frac { 27 }{ 31 } $

  2. $\frac { 31 }{ 27 } $

  3. $\frac { 4 }{ 9 } $

  4. $\frac { 5 }{ 9 } $

Show answer
Correct Option: B

If the density of a certain gas at $30^oC$ and $768 \ torr$ is $1.35 \ kg/{m}^{3}$, the density at STP would be:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $1.48 \ kg/{m}^{3}$

  2. $1.58 \ kg/{m}^{3}$

  3. $1.25 \ kg/{m}^{3}$

  4. $1.4 \ kg/{m}^{3}$

Show answer
Correct Option: A
Explanation:
From Ideal gas law,

$PM = dRT$

$P _1 = 768\ torr$
$T _1 = 30^0\ C = 303\ K$
$d _1 = 1.35 kg/ m^3$

At STP, 
$T _2 = 273\ K$
$P _2 = 760\ torr$

$\dfrac{P _1}{P _2} = \dfrac{d _1T _1}{d _2T _2}$

$\dfrac{768}{760} = \dfrac{1.35\times 303}{d _2\times 273}$

$d _2 = 1.48 kg/m^3$

Hence, option A is correct.

$5$ moles of $SO _{2}$ and 5 moles of $O _{2}$ are allowed to react to form $SO _{3}$  in a closed vessel. At the equilibrium stage, $60\%$ $SO _{2}$ is used up. The total number of moles of $SO _{2}$, $O _{2}$ and $SO _{3}$ in the vessel now is

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $10.5$

  2. $10.0$

  3. $8.5$

  4. $3.9$

Show answer
Correct Option: B

For an isolated system, the wall/boundary separating the system from surrounding must be

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. rigid

  2. impermeable

  3. adiabatic

  4. diathermal

Show answer
Correct Option: A,B,C

Assertion: Heat is not a state function

Reason: The change of heat depends upon the

path followed

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. both A and R are true and R is the correct explanation of A.

  2. both A and R are true but R is not the correct explanation of A.

  3. A is true but R is false.

  4. both A and R are false.

Show answer
Correct Option: A
Explanation:

Heat is a path function. The change of heat depends upon the path followed

Which of the following statement(s) is/are incorrect?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. For a closed system at rest with no fields, the sum of $q+w$ has the same value for every process that goes from a given state 1 to a given state 2

  2. If a closed system at rest in the absence of external field undergoes an adiabatic process that has $w=0$, then the temperature of system must remain constant

  3. A change in state from state 1 to state 2 produces a greater increase in entropy of the sytem when carried out irreversible than when carried out reversibly

  4. The change in entropy of the system for an adiabatic process in a closed system must be zero

Show answer
Correct Option: B,C,D

A container of volume $1{m}^{3}$ is divided into two equal parts by a partition. One part has an ideal diatomic gas at $300K$ and the other part has vacuum. The whole system is isolated from the surrounding. When the partition is removed, the gas expands to occupy the whole volume. Its temperature will be:

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. $300K$

  2. ${ 227.5 }^{ o }C$

  3. $455K$

  4. ${455}^{o}C$

Show answer
Correct Option: A

Select the correct statements.

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. State of a system is assumed to be in internal equilibrium and the temperature and pressure are uniform throughout the system.

  2. Thermal drift in a system with time is more in Dewar flask than in insulated system.

  3. Thermal drift in a system with time is more in non-insulated system than in insulated system.

  4. Thermal drift in a system with time is more in insulated system than in non-insulated system.

Show answer
Correct Option: A,C
Which of the following is not a state function?
chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Temperature

  2. Density

  3. Work

  4. Volume

  5. Pressure

Show answer
Correct Option: C
Explanation:

Temperature, density, volume and pressure are state functions.
They are intrinsic properties of the system. Their values  depend on initial and final state only and are independent of path followed.
On the other hand, work is a path function. It is not an state function. Its value depends on the path followed.

Select the conditions which represent the criteria for spontaneity of a process in a closed system, from the following given conditions:


Serial Number Conditions
1. ${ \left( dG \right)  } _{ P,T }>0$
2. ${ \left( \Delta S \right)  } _{ universe }>0$
3. ${ \left( dU \right)  } _{ S,V }>0$
4. ${ \left( dH \right)  } _{ S,P }<0$
5. ${ \left( dS \right)  } _{ u,V }<0$
6. ${ \left( dS \right)  } _{ H,P }>0\quad $

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. 1 & 4

  2. 1 & 2

  3. 3 & 5 

  4. 4 & 6

Show answer
Correct Option: B

Which of the following factors is of no significance for roasting sulphide ores to the oxides and not subjecting the sulphide ores to carbon reduction directly?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Metal sulphides are thermodynamically more stable than $CS _2$

  2. $CO _2$ is thermodynamically more stable than $CS _2$

  3. Metal sulphides are less stable than the corresponding oxides

  4. $CO _2$ is more volatile than $CS _2$

Show answer
Correct Option: A
Explanation:

The reduction of metal sulfides by carbon reduction process is not spontaneous as the change in Gibb's free energy ($\triangle G$) for such a process is positive. 

The reduction of metal oxides by carbon reduction process is spontaneous as $\triangle G$ for such a process is negative.
Thus $CO _2$ is more stable than $CS _2$ and the metal sulfides are more stable than the corresponding oxides.
Hence, factor listed in $(3)$ is of no. significance.

Which of the following is a state function and also an extensive property?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Internal energy

  2. Pressure

  3. Molar heat capacity

  4. Temperature

Show answer
Correct Option: A
Explanation:

$\Delta E=nCv\Delta T$ (depend on n)

Which of the following is not a thermodynamic state function?

chemistry chemical thermodynamics system and surroundings introduction to thermodynamics basics of thermodynamics

  1. Work

  2. Internal energy

  3. Free energy

  4. Temperature

Show answer
Correct Option: A
Explanation:

Work depend as path, so it is a path function.

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