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Materials around us and different types of houses - class-IX

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.......................... is more dense in liquid state than in solid.

  1. Water

  2. Alcohol

  3. Acetone

  4. All of above


Correct Option: A
Explanation:

Water is the only substance that is more dense in a liquid state than in a solid state. Liquid water is most dense when it is cold and salty. 

Which of the following is a property of liquid?

  1. fixed volume

  2. no fixed shape

  3. no distinct boundaries

  4. all of the above


Correct Option: D
Explanation:

Liquids have no fixed shape but have a fixed volume. They take up the shape of the container in which they are kept. Hence do not have distinct boundaries.

Which of the following is true for gases?

  1. Gases do not have a fixed volume.

  2. Gases do not have a fixed shape.

  3. Gases are not rigid.

  4. All of the above.


Correct Option: D
Explanation:

Gases neither have a definite shape nor  have a definite  volume. They fill up the container completely. They are not rigid.

Which of the following have a definite shape and volume?

  1. Solids

  2. Liquids

  3. Gases

  4. All of the above


Correct Option: A
Explanation:

Solids have a definite shape and volume. For example, gold is solid and it has both shape and volume.

Hence (A) is the correct option.  

Liquids are known to have density lower than solid because:

  1. the number of particles is less and the inter-molecular space is minimum

  2. the number of particles is less and the inter-molecular space is more.

  3. the number of particles is least and the inter-molecular space is more.

  4. the number of particles is less and the inter-molecular space is maximum.


Correct Option: B

The combustion of candles, containing paraffin wax, to carbon dioxide and water vapor is:

  1. sublimation as well as chemical reaction with oxygen

  2. only sublimation

  3. not sublimation but a chemical reaction with oxygen

  4. none of above


Correct Option: C
Explanation:

The term sublimation refers to a physical change of state and is not used to describe transformation of a solid to a gas in a chemical reaction. The combustion of candles, containing paraffin wax, to carbon dioxide and water vapor is not sublimation but a chemical reaction with oxygen.

Which of the following can be a definition for solids? 

  1. A state of matter that has a definite volume but not a definite shape.

  2. A state of matter that has both a fixed volume and shape.

  3. A state of matter that does not have a definite volume or shape.

  4. A state of matter that conducts electricity well.

  5. A state of matter similar to gas that has free electrons.


Correct Option: B
Explanation:

The molecules of a solid are fixed within the solid, and they just vibrate about their mean position. 


Due to this constant positioning, solids have a fixed volume and shape.

Hence the correct option is B.

Arrange the density of three types of matter in decreasing order.

  1. gas, liquid, solid

  2. liquid, solid, gas

  3. liquid, gas, solid

  4. solid, gas, liquid

  5. solid, liquid, gas


Correct Option: E
Explanation:

Density means how much dense or rigid the particles in a matter are. 


A solid is denser than the liquid and a liquid is denser than the gas.


Thus the decreasing order of density should be solid, liquid, gas. 


Hence, the correct option is E.

According to the concept of 'panch tattvas', the matter can be classified into the air, water, sky, fire, and earth.

  1. True

  2. False


Correct Option: A
Explanation:

According to ancient philosophies, the matter was classified as air, water, earth, fire, and sky. This classification is based on the sources of matter. Since there are five sources, hence it was also called as 'panch tattvas'. 

At which temperature the density of water will be highest?

  1. $0^o C$

  2. $4^o C$

  3. $80^o C$

  4. $-4^o C$.


Correct Option: B
Explanation:
In ice, the water molecules are in a crystal structure that has a lot of empty space.

When the ice melts to liquid water, the structure collapses and the density of the liquid increases.

At temperatures well above freezing, the molecules move faster and get further apart. The density decreases as temperature increases.

Now, let's cool the water.

As the temperature of warm water decreases, the water molecules slow down and the density increases.

At 4 °C, the clusters start forming.

Cluster formation is the bigger effect, so the density starts to decrease. 
Thus, the density of water is a maximum at 4 °C.

Option (B) is correct here.

Based on the physical properties, matter can be classified as _________.

  1. solid

  2. liquid

  3. gas

  4. all of these


Correct Option: D
Explanation:

Based on the physical properties, the matter can be classified as solid, liquid, and gases.

Which of the following is liquid at ordinary temperature ?

  1. Germanium

  2. Gallium

  3. Gold

  4. Galena


Correct Option: B

 The weight is required to get 2.24 litre of oxygen at STP is :

  1. 3.4 grams

  2. 34 grams

  3. 6.8 grams

  4. 68 grams


Correct Option: A

10 gm of a gas at 1 atm and 273 K occupies 5 litres. The temperature at which the volume becomes double for the the mass of gas at the same pressure is :

  1. $273 K$

  2. $ - {273^ \circ }C\,\,$

  3. ${250^ \circ }C$

  4. ${546^ \circ }K$


Correct Option: A

26cc of $CO _2$ are passsed over red hot coke .The volume of CO evolved is :


 ${C _{\left( s \right)}} + C{O _{2\left( g \right)}} \to 2C{O _{\left( g \right)}}$ 

  1. 15cc

  2. 10cc

  3. 52cc

  4. None of these


Correct Option: C

At $0^o$C the density of nitrogen at $1$ atm is $1.25$ kg$/m^3$. The nitrogen which occupied $1500$ml at $0^o$C and $1$ atm was compressed at $0^o$C and $575$ atm and the gas volume was observed to be $3.92$ ml, in violation of Boyle's law. What was the final density of this non-ideal gas?

  1. $278$ $kg/m^3$

  2. $378$ $kg/m^3$

  3. $478$ $kg/m^3$

  4. $578$ $kg/m^3$


Correct Option: A

In an evacuated rigid vessel of volume V liter, one mole of solid ammonium carbonate, $ NH _2CONH _4 $ , is taken and the vessel is hated to T K. The equilibrium total pressure of gases is found to be P atm. The percentage dissociation of solid into $ NH _3(g) $ and $ CO _2 (g) $ is 

  1. $ \dfrac { 100RT }{ 3PV } %$

  2. $ \dfrac { RT }{ 3PV } %$

  3. $ \dfrac { 100RT }{ PV } %$

  4. $ \dfrac { 300RT }{ PV } %$


Correct Option: A

By what factor does water expand when converted into vapour at $100^o$C and $1$ atm pressure? The density of liquid water at $100^o$C and $1$ atm is $0.96$g $cm^{-3}$?

  1. $815$

  2. $2000$

  3. $1630$

  4. $500$


Correct Option: A

When water is cooled it contracts until it reaches ______ and then it starts expanding.

  1. ${37^0}C$

  2. ${40^0}C$

  3. ${0^0}C$

  4. ${4^0}C$


Correct Option: D
Explanation:

Though substances contract on cooling, water expand when cooled beyond ${4^0 C}$. This is known as anomalous behavior of water. The density of water is maximum at $4^0$$C$

A solid shape has _____ dimensions and so occupies _______.

  1. three, space

  2. two, space

  3. one, space

  4. no, space


Correct Option: A

Which of the following cannot change, in a physical change?

  1. Volume

  2. Pressure

  3. Chemical composition

  4. Temperature


Correct Option: C
Explanation:

In a physical change the chemical composition of a substance does not change. 


For example conversion of water into steam where composition remain same i.e. $H _2O$.

Volume, pressure and temperature are the physical properties.

The state in which molecular attractions are very strong is:

  1. solid

  2. liquid

  3. gas

  4. none of these


Correct Option: A
Explanation:

Solids are densely packed due to its  high intermolecular attractions so they are highly incompressible but liquid has less intermolecular attractions compared to solid.But gases have very less intermolecular attractions.So they are loosely packed.

 Space occupied is given by :

  1. solid

  2. density

  3. matter

  4. weight

  5. volume


Correct Option: E
Explanation:

Space occupied is given by volume which is generally measured in litres. Other units of volume include $dm^3$, gal and mL.


Hence the correct option is E.

Gases do not have a definite shape because:

  1. molecules exert no force of attraction or repulsion upon one another

  2. molecules exert force of attraction

  3. molecules exert force repulsion upon one another

  4. both b and c


Correct Option: A
Explanation:

The molecules exert no force of attraction or repulsion upon one another. I.e., the molecules are independent of each other. This is the reason gases do not have a definite shape.

A solid cube of iron whose edge is 4 inches weighs 20.8 lbs. Determine the specific gravity of this sample of iron, if water weighs 62.4 pounds per cubic foot?
  1. $4.5$

  2. $5.2$

  3. $9.0$

  4. $27$

  5. $324$


Correct Option: C
Explanation:

$4$ inches $=$ $0.333$ foot


Since it is a solid cube, its volume is given by the formula $(side)^3$, that is, here its volume is $(0.333)^3$, that is $0.0369$ cubic foot.


Mass of the solid cube is $20.8$ pounds

Density $=$$\dfrac{Mass}{Volume}$

Thus, the density of the solid cube is $\dfrac{20.8}{0.0369}$, that is $563.68$ pounds per cubic foot.

Mass of water is $62.4$ pounds per cubic foot.

Thus, density of water is $\dfrac{Mass}{Volume}$, that is $\dfrac{62.4}{1}$, that is $62.4$ pounds per cubic foot.

Specific gravity of the solid iron  $= \dfrac {Density\ of\ solid\ iron} {Density\ of\ water}$

Thus, specific gravity of the iron is $=$ $\dfrac{563.68}{62.4}$, that is $9.033 \approx\ 9$

Hence, the correct option is C.

 Mass per unit volume can be defined as:

  1. volume

  2. weight

  3. density

  4. matter

  5. none of the above


Correct Option: C
Explanation:

Mass per unit volume can be defined as density. For example : when 1 g of water has volume of 1 mL, the density of water will be 1 g/mL.
Density $\displaystyle = \dfrac {\text {mass}}{\text {volume}}$

Which of the following is the most precise for measuring the volume of a liquid?

  1. Test tube

  2. Graduated cylinder

  3. Burette

  4. Volumetric flask

  5. Beaker


Correct Option: D
Explanation:

Volumetric flask is the most precise for measuring the volume of a liquid.


When the values of different measurements are close to each other as well as to average value, such measurements are called precise.

Hence the correct option is D.

A liquid cannot be compressed because it has a fixed volume

  1. True

  2. False


Correct Option: A
Explanation:

A liquid cannot be compressed because its particles are closely packed due to which it has a fixed volume.

Water vapour and steam are similar because they have no definite shape and no definite ________.

  1. size

  2. mass

  3. volume

  4. temperature


Correct Option: C
Explanation:

Water vapour and steam are the gases states of matter. Gases have no definite shape and no definite volume.

The property of compressibility is :

  1. maximum in solids

  2. least in solids

  3. maximum in liquids

  4. least in gases


Correct Option: B
Explanation:

Solids are held in fixed positions, they can only vibrate. Because the particles can not move, solids have a definite shape and volume, and can't flow. Because the particles are already packed closely together, solids can't easily be compressed.

Anu wanted to find out which solid, marbles or beads, occupy more space. In order to be a fair test what things should be kept same?

  1. Amount of liquid

  2. Size of the container

  3. Number of marbles and beads

  4. Mass and volume of the marbles and beads


Correct Option: A,B,C
Explanation:

A matter is something that has mass and occupies space. Both marbles and beads are matter since they have mass and occupy space. In order to measure which one occupies more space, the amount of liquid, size of the container and number of marbles and beads are required. The amount of liquid displaced by the solid will be the space occupied by the solid. Higher the displaced volume, higher the space occupied. Since space occupied is independent of mass and hence D is incorrect

Which of the following statements about water are correct?

  1. Water has a fixed mass

  2. Water can be compressed

  3. Water takes the shape of its container

  4. Water has a fixed volume


Correct Option: A,C,D
Explanation:

Water is a liquid hence it will show all the properties of liquids, it can take the shape of container, it has fixed mass and volume and very less compressible.


Hence the correct options are A, C and D.

Water is liquid at room temperature. Which of the following is the correct reason to justify it?

  1. In water, the inter molecular forces are strong enough to keep its particle bound with each other

  2. The melting point of water is below room temperature

  3. Its boiling point is above room temperature

  4. All of above


Correct Option: D
Explanation:

The intermolecular force of attraction between the water molecules is strong enough to keep the molecules/particles bound to each other. The melting point of water is below room temperature as it is already present in the liquid state whereas, its boiling point is above room temperature, i.e; $100^oC$ and room temperature is $20^oC - 22^oC$

In which of the following state inter molecular force is maximum :

  1. solid

  2. liquid

  3. gas

  4. plasma


Correct Option: A
Explanation:

Intermolecular forces of attraction are maximum in solids and minimum in gases, as solids have definite shape, and particles are closely packed.

A table made by iron is solid because:

  1. it has fixed shape because of strong molecular forces.

  2. it can not be deformed easily because of strong molecular forces.

  3. it is metal.

  4. None of these.


Correct Option: B
Explanation:

The iron table is solid because the intermolecular force of attraction of the iron table is very strong, thus it is rigid and hence cannot be deformed.

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