AS Kinetics

Which one/ones of the following changes can affect the rate of a chemical reaction?

• concentration

• temperature

• pressure

• surface area

The graph shows how the concentration of a reactant changes with time.

Which expression gives the best estimate for the value of the rate of this reaction at time b?

Activation energy is the​ (a)   energy that ​ (b)   particles must posses for a reaction to occur.

• minimum
• colliding
• maximum
• moving
• average

The activation energy of the forward reaction has a value of

• X minus Y.

• Y minus X.

• Y minus Z.

• Z minus Y.

Consider the following reaction profile.

Which energy change would alter if a catalyst were added to the reaction?

• A

• B

• C

• D

Answer explanation

Catalyst increases the rate of a chemical reaction by providing an alternative route for the reaction.

The curve show the distribution of molecular energies at a temperature, T₁.

1. Label the axes on the diagrams.

2. Draw a curve to show the distribution of molecular energies at a higher temperature, T₂.

Catalyst ​ (a)   activation energy by providing an alternative route for the reaction. More molecules possess ​ (b)   energy than Ea. Therefore, more successful collisions will occur and rate ​ of reaction ​ (c)   .

• lowers
• greater
• increases
• less
• decreases

Match the following experimental technique to obtain rate date for a given reaction.

• measure the electrical conductivity

• 
• monitor a colour change (colorimetry)

• 
• measure the volume of a gas evolved

• 
• measure the change in mass of a reaction mixture

•