Reaction Rates

Increase in temperature of the reactants can do one of the following

• Slow collision frequency
• Allow less effective collision between the particles
• Neutralise the reaction
• increase collision between the particles thus increasing the rate.

To slow down a chemical reaction you will do one of the following:

• Place the reactants in hot water
• Place the products in ice bath
• Place the reactants in a ice bath
• Keep stirring the reactants with a stirring rod

How could we make this reaction happen more quickly?

• Decrease the concentration of the acid

• crush the chalk to increase the surface area

• Put the test tube in an ice bath

The major theory of reaction rate is called

• Collision theory

• Crash theory

• Newton's laws

• Thermodynamics

Which one of the following is NOT a key concept of the collision theory:

• particles must collide in order to react

• particles must move slowly when they collide, otherwise they simply “bounce off” one another

• particles must collide with the proper orientation

• particles must collide with sufficient energy to reach the activated complex in order to react

Activation energy is the amount of energy required to

• break the bonds between the reacting molecules

• convert the reactants into the activated complex

• make the reacting particles collide

• form the bonds between the product molecules

The activation energy, Ea, for the reverse reaction is

• + 50 kJ

• + 200 kJ

• -150 kJ

• + 150 kJ

Which one of the following statements concerning rates of reactions is FALSE?

• The higher the activation energy barrier, the faster the reaction.

• Increasing the concentration of a reactant may increase the rate of a reaction.

• Adding a catalyst speeds up the rate of reaction for both the forward and reverse reactions.

• Increasing the concentration increases the rate of a reaction, because it increases the number of collisions.

Increasing pressure causes the reacting particles

• to bond together

• to repel from each other

• gain more kinetic energy

• to move closer together

Rate of chemical reaction means

• amount of product formed
• speed of reaction
• concentration of reacting particles
• combining reactants with products