Question

The kinetics of the decomposition of dinitrogen pentaoxide is studied at 50°C and at 75°C. Which of the following statements concerning the studies is correct? (MTS 9/29/2018) Group of answer choices The rate at 75°C will be greater than the rate at 50°C because the number of molecules with enough energy to react increases with increasing temperature. The rate at 75°C will be greater than the rate at 50°C because the activation energy will be lower at 75°C than at 50°C. The rate at 75°C will be greater than the rate at 50°C because the activation energy will be higher at 75°C than at 50°C. The rate at 75°C will be less than the rate at 50°C because the molecules at higher speeds do not interact as well as those at lower speeds. The rate at 75°C will be greater than at 50°C because the concentration of a gas increases with increasing temperature.

Answer 1

The following statement is correct: The rate at 75°C will be greater than the rate at 50°C because the number of molecules with enough energy to react increases with increasing temperature.

Step-by-step explanation:

• The rate at 75°C will be greater than the rate at 50°C because the number of molecules with enough energy to react increases with increasing temperature. TRUE. According to the collision theory, for a reaction to take place it is necessary that molecules collide with enough energy and with proper orientation. At higher temperatures, a larger number of molecules have enough energy for the collision to be effective and the rates of formation of products and disappearance of reactants increase.

• The rate at 75°C will be greater than the rate at 50°C because the activation energy will be lower at 75°C than at 50°C. FALSE. The activation energy depends on the mechanism of the reaction and it does not depend on the temperature.
• The rate at 75°C will be greater than the rate at 50°C because the activation energy will be higher at 75°C than at 50°C. FALSE. As said previously, activation energy does not depend on the temperature.
• The rate at 75°C will be less than the rate at 50°C because the molecules at higher speeds do not interact as well as those at lower speeds. FALSE. At higher temperatures, there are higher probabilities that molecules collide and that they do so with enough energy so as to overcome activation energy.
• The rate at 75°C will be greater than at 50°C because the concentration of a gas increases with increasing temperature. FALSE. The concentration of a gas decreases with increasing temperature because volume increases.