Some reactions are exothermic and some reactions are endothermic - Edexcel - GCSE Chemistry - Question 4 - 2022 - Paper 1
Question 4
Some reactions are exothermic and some reactions are endothermic.
(a) What does an exothermic reaction always give out?
☐ A heat energy
☐ B light
☐ C a gas ... show full transcript
Worked Solution & Example Answer:Some reactions are exothermic and some reactions are endothermic - Edexcel - GCSE Chemistry - Question 4 - 2022 - Paper 1
Step 1
What does an exothermic reaction always give out?
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Answer
An exothermic reaction always gives out heat energy. Therefore, the correct answer is A.
Step 2
Give the letter of the piece of apparatus, A, B, C or D, in Figure 6 that is used to measure the temperature.
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Answer
The piece of apparatus that is used to measure the temperature is A, which is a thermometer.
Step 3
Give the name of the piece of apparatus B shown in Figure 6.
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Answer
The name of the piece of apparatus B shown in Figure 6 is a beaker.
Step 4
State why polystyrene is a better material than glass for this piece of apparatus.
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Answer
Polystyrene is a better material than glass because it is a good heat insulator. This means it can hold or trap heat in, reducing heat loss.
Step 5
Calculate the change in temperature.
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Answer
To calculate the change in temperature, we have:
temperature change=temperature of liquid at start−temperature of products at end
Substituting the values:
temperature change=18.6°C−16.1°C=2.5°C
The change in temperature is +2.5 °C.
Step 6
Give the formula and the name of the solid.
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Answer
The formula for the solid used in this experiment is NH₄NO₃, which is called ammonium nitrate.
