Paper 2: Section 7- Rates of Reaction and Energy Changes

Question 1

How do you calculate the rates of reaction?

Answer 1

amount of reactant used or amount of product formed/ time

Question 2

Name 3 ways you can follow reaction rates:

Answer 2

1. Precipitation
2. Change in mass
3. The volume of gas given off

Question 3

Finish the sentence: When you mix two see- through solutions it produces…

Answer 3

a precipitate

Question 4

How can you use precipitation to follow reaction rates?

Answer 4

. Mark a piece of paper
. Mix the two reactants in a flask and place it on the paper
. Measure how long it takes for the mark to disappear

Question 5

Why isn’t the precipitate method the most reliable?

Answer 5

The result is subjective as people may disagree on when the mark disappears.

Question 6

How can you measure the change in mass to follow reaction rates that produce a gas?

Answer 6

. Place the reaction on a mass balance
. The quicker the mass drops, the faster the reaction
. The reaction has stopped once the mass stops changing

Question 7

Why must you take extra precautions when a harmful gas is used in the change of mass experiment?

Answer 7

The method releases the gas produced straight into the room.

Question 8

What is a safety precaution you can take in the change of mass experiment?

Answer 8

A fume cupboard

Question 9

How can you follow reaction rates by measuring the volume of gas given off?

Answer 9

. Collect the gas in a syringe to measure the volume
. The more gas given off during a set interval, the faster the reaction
. Its finished when no more gas is produced

Question 10

Collision theory: In order for a reaction to occur, particles must _______ together with enough energy.

Answer 10

collide

Question 11

Finish the sentence: The rates of reaction are increased when…

Answer 11

the frequency and/or energy of collisions is increased.