RATES OF REACTION

Why does a higher temperature increase the rate of a reaction?

• it increases both the frequency and energy of particle collisions
• it only increases the frequency of particle collisions
• it only increases the energy of particle collisions
• it reduces the activation energy of the reaction

What is the activation energy?

• The energy of the products
• The energy of the reactants
• The minimum energy needed by the reactants to form the products.
• The energy lost in the reaction

The graph shows a typical energy distribution for particles of an ideal gas in a sealed container at a fixed temperature.   Which of the following statements is true?

• Position A represents the mean energy of a molecule in the container.
• Addition of a catalyst moves the position of E_A to the right.
• The area under the curve to the right of E_A represents the number of molecules with enough energy to react.
• The position of the peak of the curve at a higher temperature is further away from both axes.

The diagram shows the Maxwell−Boltzmann distribution of molecular energies in a gas at two different temperatures.

Which letter represents the most probable energy of the molecules at the higher temperature?

• A

• B

• C

• D

How does a catalyst work in speeding up a reaction?

• By lowering the activation energy or reaction

• by making them more available

• by giving them more energy