Unit 15: Reaction Rates

Question 1

Collision Theory of Reactions

Answer 1

A chemical reaction only takes place if collisions between molecules have the right energy and the right orientation

Question 2

Activation Energy

Answer 2

the minimum energy needed for a reaction to take place upon proper collision of reactants

Question 3

Reaction Rate

Answer 3

• the speed at which reactant is used up
• the speed at which product forms

Question 4

When temperature increases the reaction rate…

Answer 4

increases

Question 5

Why does the reaction rate increase when temperature increases?

Answer 5

molecules move FASTER, providing more colliding molecules with energy of activation

Question 6

When concentration of reactant increases the reaction rate…

Answer 6

increases

Question 7

Why does the reaction rate increase when the concentration increases?

Answer 7

increases the number of collisions and increases the amount of product

Question 8

Qualities of a catalyst (3)

Answer 8

1. Speeds up the rate of a reaction.
2. Lowers the energy of activation.
3. Is not used up during the reaction.

Question 9

The smaller the particle size the ____ the reaction rate

Answer 9

higher

Question 10

Why do smaller particles allow for increased reaction rates?

Answer 10

SMALLER particle size = HIGHER surface area for a given mass of particles.

Question 11

What can increase surface area of particles?

Answer 11

dissolving or by grinding into a fine powder