Question 1

According to collision theory, which TWO conditions must be met for a chemical reaction to occur between molecules?

Accepted Answer

Molecules must collide with sufficient energy and in the correct orientation.

Question 2

Which of the following best describes the role of activation energy ($$E_a) in a $$chemical reaction?

Accepted Answer

It is the minimum energy required for reactant molecules to break bonds and form products.

Question 3

A reaction between ethene ($$CH_2$$=$$CH_2) $$and hydrochloric acid ($$HCl) $$only occurs if the $$HCl$$ collides with which part of the ethene molecule?

Accepted Answer

The double bond

Question 4

Which statement about the Maxwell-Boltzmann distribution is correct?

Accepted Answer

It shows that particles in a sample have a range of kinetic energies, with only some having enough energy to react.

Question 5

In an exothermic reaction, how does the energy of the products compare to the energy of the reactants?

Accepted Answer

The products have lower energy than the reactants.

Question 6

Why do most collisions between reactant molecules NOT result in a chemical reaction?

Accepted Answer

Because most collisions do not have both sufficient energy and correct orientation.

Question 7

Which of the following changes would increase the rate of a reaction according to collision theory?

Accepted Answer

Increasing the temperature, which increases the number of particles with energy greater than $$E_a.$$

Question 8

A reaction has a high activation energy. What can be inferred about its rate under standard conditions?

Accepted Answer

It will generally have a low rate of reaction.

Question 9

Which scenario best illustrates the importance of molecular orientation in a chemical reaction?

Accepted Answer

Two molecules collide, but only react when their reactive sites are aligned.

Question 10

On a Maxwell-Boltzmann distribution graph, what does the area under the curve to the right of the activation energy ($$E_a) $$represent?

Accepted Answer

The number of particles with enough energy to react.

Question 11

If a catalyst is added to a reaction, which of the following best describes its effect?

Accepted Answer

It lowers the activation energy ($$E_a$$), increasing the rate of reaction.

Question 12

Which of the following is a real-world example of the importance of activation energy in a chemical process?

Accepted Answer

Gasoline does not ignite at room temperature because the activation energy for combustion is not reached.

Question 13

Which of the following statements about endothermic reactions is correct?

Accepted Answer

The products have higher energy than the reactants.

Question 14

A student increases the concentration of reactants in a solution. According to collision theory, what is the expected effect on the reaction rate?

Accepted Answer

The reaction rate increases due to more frequent collisions.

Question 15

Which of the following best explains why increasing temperature increases reaction rate?

Accepted Answer

More particles have kinetic energy equal to or greater than the activation energy ($$E_a).$$

Question 16

During a reaction, the activated complex (transition state) is formed. Which statement is true about the energy of the activated complex?

Accepted Answer

It has higher energy than both reactants and products.

Question 17

Which of the following would NOT increase the probability of a successful collision?

Accepted Answer

Decreasing the temperature of the reaction mixture.

Question 18

A pharmaceutical company wants to speed up a drug synthesis reaction. Which strategy, based on collision theory, would be most effective?

Accepted Answer

Increase the temperature to raise the number of particles with energy above $$E_a.$$

Question 19

Which of the following best describes the relationship between activation energy and reaction rate?

Accepted Answer

Lower activation energy leads to a higher reaction rate.

Collision Theory and Reaction Kinetics in Organic Chemistry

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