Energy Changes | AQA GCSE Chemistry, Foundation tier (8462)
Energy Changes
- 76 questions
- 5 subtopics
- Paper 1
- Paper 1
Energy Changes is examined in Chemistry Paper 1.
It covers exothermic and endothermic reactions, everyday uses, and investigating temperature change, reaction profiles, cells and batteries and fuel cells.
Sample questions from Energy Changes
Answer each one closed book first, then open the answer.
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Exothermic and endothermic reactions
A student mixes two solutions in a beaker and the beaker becomes warm. What type of energy change has taken place?
Show the answer
An exothermic change, because energy has been transferred from the reaction to the surroundings. -
Exothermic and endothermic reactions
Give two everyday products that make use of exothermic reactions.
Show the answer
Self-heating cans and hand warmers. -
Everyday uses, and investigating temperature change
Why does a thermometer standing in a reaction mixture tell you about the energy change of the reaction?
Show the answer
It records the temperature of the surroundings of the reacting particles, which rises when energy is given out and falls when energy is taken in. -
Everyday uses, and investigating temperature change
Name four kinds of reaction between solutions that are suitable for investigating temperature change.
Show the answer
An acid with a metal, an acid with a carbonate, a neutralisation, and the displacement of one metal by another from its salt solution. -
Reaction profiles
What three things can a reaction profile show about a reaction?
Show the answer
The relative energies of the reactants and products, the activation energy, and the overall energy change. -
Reaction profiles
Why is the line on a reaction profile a curve rising to a peak rather than a straight step between two levels?
Show the answer
It shows that energy must first be supplied to reach the activation energy before the energy falls again as the new bonds form. -
Cells and batteries
Why must the two electrodes in a simple cell be made from different metals?
Show the answer
Two identical metals have the same reactivity, so no voltage would be produced. -
Cells and batteries
Suggest one disadvantage of non-rechargeable batteries.
Show the answer
They have to be thrown away once a reactant is used up, which creates waste and means buying replacements.
The 5 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Exothermic and endothermic reactions | Conservation of energy in reactions, exothermic reactions that transfer energy to the surroundings and raise their temperature, examples such as combustion, oxidation and neutralisation, self-heating cans and hand warmers, and endothermic reactions that take in energy and lower the temperature of the surroundings. | 15 |
| Everyday uses, and investigating temperature change | Thermal decomposition and the citric acid and sodium hydrogencarbonate reaction, cold packs, hand warmers, reading energy change from a thermometer, and measuring temperature change in an insulated cup with the variables controlled. | 17 |
| Reaction profiles | The two conditions for colliding particles to react, activation energy and why not every collision leads to a reaction, what a reaction profile shows, reading the overall energy change and activation energy from it, and the profiles of exothermic and endothermic reactions. | 15 |
| Cells and batteries | How chemical reactions in a cell produce a current, how the electrodes and electrolyte set its voltage, making a simple cell, batteries as cells in series, why non-rechargeable cells stop working, recharging with an external current, comparing the two types, and linking voltage to differences in metal reactivity. | 17 |
| Fuel cells | Fuel cells supplied with hydrogen and oxygen, electrochemical oxidation of the fuel, water as the only product and the word equation for the overall reaction, and hydrogen fuel cells compared with rechargeable batteries for refuelling time, pollution, hazards, journey length and mass. | 12 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
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Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
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Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
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Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby topics
AQA GCSE Chemistry, Foundation tier Active Recall Guide
Every topic, not just this one. 1,386 questions with their answers.