Topic 7- Rates Of Reaction

Question 1

Equation for rates of reaction

Answer 1

Rate of reaction= amount of reactant used / time

Question 2

What methods can be used to find the rate of reaction?

Answer 2

• precipitate
• change in mass
• the volume of gas given off

Question 3

Explain how to find the rate of reaction using precipitation

Answer 3

• mix the two solutions
• put the flask on a piece of paper with a mark on it
• observe how long it takes for you to no longer be able to see the mark

Question 4

Explain how to find the rate of reaction using change in mass

Answer 4

• as gas is released the total mass is easily measured on the balance
• the quicker the reading on the balance drops the faster the reaction

Question 5

Explain how to find the rate of reaction using volume of gas given off

Answer 5

• this involves the use of a gas syringe to measure the volume of gas given off
• the more gas given off during a set interval,
• the faster the reaction the more gas will be given off in a set amount of time

Question 6

What are catalysts?

Answer 6

• increase rate of reaction

* don’t get used up in the reaction

Question 7

Exothermic

Answer 7

• gives out energy into the surroundings

* usually in the form of heat

Question 8

Endothermic

Answer 8

• takes in energy from the surroundings

* usually in the form of heat (fall in temperature of the surroundings)

Question 9

Equation for bond energies

Answer 9

Overall energy change= energy required to break bonds- energy released by forming bonds

Question 10

What happens to bonds during chemical reactions?

Answer 10

Old bonds are broken and new bonds are formed

Question 11

What happens to bonds during exothermic reactions?

Answer 11

Energy is released when new bonds are released

Question 12

What happens to bonds during endothermic reactions?

Answer 12

Energy must be supplied to break existing bonds