1.
State what is meant by an exothermic reaction. [1]
JD SCIENCE
Unit 5 worksheet — Energy changes
Answer all questions. Show working. Answers are in a separate file on the Worksheets page — do not look at them until you have finished.
2.
State what is meant by an endothermic reaction. [1]
3.
State what is meant by activation energy. [1]
4.
State what is meant by a reaction profile. [1]
5.
State what is meant by bond energy. [1]
6.
State what is meant by a catalyst. [1]
7.
State what is meant by cells and batteries. [1]
8.
State what is meant by a fuel cell. [1]
9.
State what is meant by conservation of energy in reactions. [1]
10.
State what is meant by a chemical cell. [1]
11.
Amira is asked about an exothermic reaction in a AQA Chemistry paper.
(a) Describe an exothermic reaction. [2]
(b) Explain why an exothermic reaction is important in this topic. [3]
12.
Amira is asked about an endothermic reaction in a AQA Chemistry paper.
(a) Describe an endothermic reaction. [2]
(b) Explain why an endothermic reaction is important in this topic. [3]
13.
Amira is asked about activation energy in a AQA Chemistry paper.
(a) Describe activation energy. [2]
(b) Explain why activation energy is important in this topic. [3]
14.
Amira is asked about a reaction profile in a AQA Chemistry paper.
(a) Describe a reaction profile. [2]
(b) Explain why a reaction profile is important in this topic. [3]
15.
Amira is asked about bond energy in a AQA Chemistry paper.
(a) Describe bond energy. [2]
(b) Explain why bond energy is important in this topic. [3]
16.
Amira is asked about a catalyst in a AQA Chemistry paper.
(a) Describe a catalyst. [2]
(b) Explain why a catalyst is important in this topic. [3]
17.
Bonds broken 2000 kJ, bonds made 2500 kJ. Energy change? [3]
18.
Q = mcΔT. 50 g water, c=4.2, ΔT=12°C. Calculate Q. [3]
19.
That Q came from 0.010 mol of fuel. Energy per mole? [3]
20.
A reaction profile has reactants at 80 kJ and products at 30 kJ. ΔH? [3]
21.
Ea is 60 kJ/mol without a catalyst and 25 kJ/mol with. By how much has Ea fallen? [3]
22.
A fuel cell uses 2H₂ + O₂ → 2H₂O. Moles of H₂O from 4 mol H₂? [3]
23.
Amira carries out temperature change of neutralisation or displacement. This is a typical AQA required-practical style question.
(a) Identify the independent variable and the dependent variable. [2]
(b) State one control variable and explain why it must be controlled. [2]
(c) Suggest one improvement or source of error and how it affects the result. [2]
24.
Amira carries out comparing fuels by heating water. This is a typical AQA required-practical style question.
(a) Identify the independent variable and the dependent variable. [2]
(b) State one control variable and explain why it must be controlled. [2]
(c) Suggest one improvement or source of error and how it affects the result. [2]
25.
Amira carries out drawing reaction profiles from experimental ΔT data. This is a typical AQA required-practical style question.
(a) Identify the independent variable and the dependent variable. [2]
(b) State one control variable and explain why it must be controlled. [2]
(c) Suggest one improvement or source of error and how it affects the result. [2]
26.
Amira carries out investigating chemical cells with different metal pairs. This is a typical AQA required-practical style question.
(a) Identify the independent variable and the dependent variable. [2]
(b) State one control variable and explain why it must be controlled. [2]
(c) Suggest one improvement or source of error and how it affects the result. [2]
27.
Compare exothermic with endothermic. [4]
28.
Compare a battery with a hydrogen fuel cell. [4]
29.
Compare bond breaking with bond making. [4]
30.
Compare a catalyst with an increased temperature. [4]
31.
Apply your knowledge of cells and batteries to this situation: the reaction is reversed when charging [3]
32.
Apply your knowledge of a fuel cell to this situation: only water emitted vs hydrogen storage issues [3]