Tag: how far? how fast?

Questions Related to how far? how fast?

What happen with the rate of the reaction when the frequency and the number of effective collisions between reacting particles increases?

chemistry how far? how fast? collision theory collision theory of chemical reactions rate of chemical reaction

  1. Increases

  2. Decreases

  3. Remains the same

  4. Approaches zero

  5. None of the above

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Correct Option: A
Explanation:

The atoms, ions and molecules can react to form products when they collide with enough kinetic energy and at favorable orientation. On increasing the frequency and the number of effective collisions between reacting particles increases the chance of reactants to come together to form a product  that results in the increase of rate of the reaction. 

What causes an increase in effective collisions without increasing average energy?

chemistry how far? how fast? collision theory collision theory of chemical reactions rate of chemical reaction

  1. An increase in the reactant concentration

  2. An increase in the temperature

  3. A decrease in pressure

  4. Catalysts

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Correct Option: A
Explanation:

As the concentration of the reactant increases, effective collision between the reactant molecules also increases. And thus, the reaction rate also increases. It is the main principle of the collision theory.

Option  A is the correct answer.

Collision diameter is least in case of:

chemistry how far? how fast? collision theory collision theory of chemical reactions rate of chemical reaction

  1. ${ H } _{ 2 }$

  2. $He$

  3. ${ CO } _{ 2 }$

  4. ${ N } _{ 2 }$

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Correct Option: C
Explanation:

Collision diameter will be least for the low molecular weight.


$d\space \alpha\space \dfrac{1}{M}$

In this case, $Co _2$ has the highest molecular weight.

So, Option C is correct

Collision frequency of a gas at $1\ atm$ pressure is $Z$. Its value at $0.5\ atm$ will be:

chemistry how far? how fast? collision theory collision theory of chemical reactions rate of chemical reaction

  1. $0.25Z$

  2. $2Z$

  3. $0.50Z$

  4. $Z$

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Correct Option: D
Explanation:

$\rightarrow$ As the pressure increases collision frequency increases.

$\rightarrow$ Vice versa pressure is decreased to half, frequency of collision decreases to half.
Hence option $C$ is correct.

If X is the total number of collisions which a gas molecule registers with other molecules per unit time under particular conditions, then the collision frequency of the gas containing N molecules per unit volume is?

chemistry how far? how fast? collision theory collision theory of chemical reactions rate of chemical reaction

  1. X/N

  2. NX

  3. $2NX$

  4. $NX/2$

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Correct Option: D

The number of collisions of Ar atoms with the walls of container per unit time?

chemistry how far? how fast? collision theory collision theory of chemical reactions rate of chemical reaction

  1. Increases when the temperature increases

  2. Remains the same when $CO _2$ is added to the container at constant temperature

  3. Increases when $CO _2$ is added to the container at constant temperature

  4. Decreases, when the average kinetic energy per molecule is decreased

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Correct Option: A

In a closed flask of $5$l $1.0$g $H _2$ is heated from $300$ to $600$K. Which statement is not correct?

chemistry how far? how fast? collision theory collision theory of chemical reactions rate of chemical reaction

  1. Pressure of the gas increases

  2. The rate of collisions increases

  3. The number of moles of gas increases

  4. The energy of gas molecules increases

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Correct Option: A

One mole of helium and one mole of neon are taken in a vessel. Which of the following statements are correct?

chemistry how far? how fast? collision theory collision theory of chemical reactions rate of chemical reaction

  1. Molecules of helium strike the wall of vessel more frequently

  2. Moles of neon apply more average force per collision on the wall of vessel

  3. Molecules of helium have greater average molecular speed

  4. Helium exerts higher pressure than neon

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Correct Option: A

When the temperature of an ideal gas is increased at constant pressure?

chemistry how far? how fast? collision theory collision theory of chemical reactions rate of chemical reaction

  1. Collision number increases

  2. Collision frequency increases

  3. Mean free path increases

  4. Number of molecules per unit volume increases

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Correct Option: A

An increase in the rate of a reaction for a rise in temperature is due to:

chemistry how far? how fast? collision theory collision theory of chemical reactions rate of chemical reaction

  1. increase in collision frequency

  2. shortening of mean free path

  3. increase in the number of activated molecules

  4. none of the above

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Correct Option: A,B,C
Explanation:

An increase in the rate of a reaction for a rise in temperature is due to  increase in collision frequency, shortening of mean free path and increase in the number of activated molecules.
Increasing the temperature increases reaction rates because of the disproportionately large increase in the number of high energy collisions. It is only these collisions (possessing at least the activation energy for the reaction) which result in a reaction.