Rates of reaction

Question 1

What are the two ways of measuring the rate of reaction?

Answer 1

1. Measure the rate at which a reactant is used up
2. Measure the rate at which a product is formed

Question 2

What is the equation for figuring out the rate of reaction?

Answer 2

Rate of reaction =

amount of reactant used or formed

÷

time taken

Question 3

if 24 cm3 of hydrogen gas is produced in two minuteswhat is the mean rate of reaction?

Answer 3

24 ÷ 2 = 12 cm3 hydrogen / min.

Question 4

What increases the rate of reaction?

Answer 4

1. The temperature is increased
2. The concentration of a dissolved reactant is increased
3. The pressure of a reacting gas is increased
4. Solid reactants are broken into smaller pieces
5. A catalyst is used

Question 5

What happens when two reactents collide with too little energy?

Answer 5

Collisions with too little energy do not produce a reaction.

Question 6

what happens if the concentration of a dissolved reactant is increased, or the pressure of a reacting gas is increased?

Answer 6

1. There are more reactant particles in the same volume
2. There is a greater chance of the particles colliding
3. The rate of reaction increases

Question 7

What happens if a solid reactant is broken into small pieces or ground into a powder?

Answer 7

1. Its surface area is increased
2. More particles are exposed to the other reactant
3. There is a greater chance of the particles colliding
4. The rate of reaction increases

Question 8

What happens if the temperature is increased?

Answer 8

1. The reactant particles move more quickly
2. More particles have the activation energy or greater
3. The particles collide more often, and more of the collisions result in a reaction
4. The rate of reaction increases

Question 9

What happens when a catalyst is used?

Answer 9

Catalysts increase the rate of reaction without being used up. They do this by lowering the activation energy needed. With a catalyst, more collisions result in a reaction, so the rate of reaction increases. Different reactions need different catalysts.