Rates of Reaction and Energy Changes | Edexcel GCSE Chemistry, Higher tier (1CH0)
Rates of Reaction and Energy Changes
- 126 questions
- 7 subtopics
- Paper 2
- Paper 2
Rates of Reaction and Energy Changes is examined in Paper 2, Chemistry 2.
It covers investigating the rate of a reaction, measuring rate and interpreting rate graphs, collision theory and factors affecting rate, catalysts and enzymes, exothermic and endothermic changes, bond breaking, bond making and the overall energy change and bond energies, activation energy and reaction profiles.
Sample questions from Rates of Reaction and Energy Changes
Answer each one closed book first, then open the answer.
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Investigating the rate of a reaction
Why is following loss of mass unsuitable when the gas produced is hydrogen?
Show the answer
Hydrogen has such a low mass that the balance shows almost no change. -
Investigating the rate of a reaction
Why must the same flask and the same total volume of liquid be used for every run of the sodium thiosulfate experiment?
Show the answer
The amount of sulfur needed to hide the cross depends on the depth of liquid, so it must be kept constant for a fair comparison. -
Measuring rate and interpreting rate graphs
Suggest why a datalogger connected to a balance gives better results than reading the balance by eye.
Show the answer
A datalogger records readings at exactly equal intervals and does not miss a reading, so the data are more reliable. -
Measuring rate and interpreting rate graphs
A flask loses 2.4 g of mass in 120 s. Calculate the mean rate of the reaction in g s⁻¹.
Show the answer
2.4 ÷ 120 = 0.02 g s⁻¹. -
Collision theory and factors affecting rate
Explain why a reaction between two solids is usually extremely slow.
Show the answer
Only the particles at the touching surfaces can collide, so collisions are very infrequent. -
Collision theory and factors affecting rate
Explain, in terms of collisions, why food kept in a refrigerator stays fresh for longer.
Show the answer
At the lower temperature particles collide less often and with less energy, so the reactions that spoil food are slower. -
Catalysts and enzymes
Give one economic reason why industry uses catalysts.
Show the answer
A catalyst lets the same amount of product be made faster and at lower temperatures, which saves energy and money. -
Catalysts and enzymes
Name a group of drinks whose manufacture depends on enzymes.
Show the answer
Alcoholic drinks such as beer and wine.
The 7 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Investigating the rate of a reaction | Following marble chips and acid by gas volume or loss of mass, the variables and errors, and timing the disappearing cross when sodium thiosulfate reacts with hydrochloric acid. | 23 |
| Measuring rate and interpreting rate graphs | Methods for following a reaction by gas, colour, precipitate, mass or pH, why timing starts at mixing, reading rate from the gradient of a graph, and calculating mean rates. | 18 |
| Collision theory and factors affecting rate | The conditions for a successful collision, collision frequency and energy, how temperature, concentration, surface area and pressure affect rate, why reactions slow as reactants are used up, and calculating surface area to volume ratios. | 20 |
| Catalysts and enzymes | What a catalyst is and why it is not used up and changes neither the products nor the yield, why industry uses catalysts, how a lower activation energy pathway speeds a reaction, and enzymes in fermentation and their damage at high temperatures. | 17 |
| Exothermic and endothermic changes | Heat energy changes when salts dissolve and in neutralisation, displacement and precipitation, measuring temperature changes in an insulated cup, exothermic and endothermic changes with everyday examples, and how the energy stored in products compares with reactants. | 18 |
| Bond breaking, bond making and the overall energy change | Why breaking bonds is endothermic and making them exothermic, which bonds break and form in a reaction, the conditions for an overall exothermic or endothermic change, and the sign of the energy change. | 11 |
| Bond energies, activation energy and reaction profiles | Working out the overall energy change from bond energies for HCl, HBr and NO, what activation energy is and why a spark is needed, and reading reaction profiles including a catalysed route. | 19 |
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
Edexcel GCSE Chemistry, Higher tier Active Recall Guide
Every topic, not just this one. 1,857 questions with their answers.