Which of the following would NOT increase the rate of reaction:?

a) As temperature rises, more reactant particles would have energy greater than the activation energy. Therefore, the rate of reaction increases.

b) A catalyst would increase the rate of the reaction but without chemical change at the end of the reaction.

c) As the concentration increases, the number of collisions of reactant particles increases. This leads to faster reaction rate.

d) When the surface area of a solid reactant increases, the number of collisions towards the solid reactant increases. Therefore, the rate of reaction increases.

e) When the volume the container for a gaseous reaction increases, the pressure of the system decreases. This leads to the decreases in number of collisions between the gaseous reactant molecules. Therefore, the reaction rate decreases.

The answer: e) increasing the volume of the container for a gaseous reaction

Would not increase the rate of reaction:

e. Increasing the volume, since that will decrease the concentration

Factors which affect the rate of reaction.....
1. Concentration
2. Temperature
3. Particle size / surface area
4. Catalyst

Collision theory: a chemical reaction occurs when two particles collide with a combined energy equal to or greater than the activation energy. Any factor which affects the collision frequency or energy will affect the reaction rate.

Increasing the concentration will result in more collisions and increased rate. Increasing the temperature will speed up the molecules which result in more collisions and greater energy, both of which will increase the rate. Increasing the surface area (by decreasing the particle size) will allow for more collisions and increase the rate. A catalyst is a reactant in an early step in the reaction mechanism and a product in a later step so that it appears that the catalyst does not react. The catalyst provides an alternate reaction pathway with a lower activation energy which means that more molecules will react, increasing the rate.

e

E : more volume = more room for reactants to move and perhaps less room/ chances to collide and potentially react. So increasing the volume may actually slow down the reaction.

All the other options would increase the rate

'e'