A student investigated the rate of reaction between calcium carbonate (marble chips) and hydrochloric acid - AQA - GCSE Chemistry - Question 1 - 2015 - Paper 2
Question 1
A student investigated the rate of reaction between calcium carbonate (marble chips) and hydrochloric acid.
The student used the apparatus shown in Figure 1.
The s... show full transcript
Worked Solution & Example Answer:A student investigated the rate of reaction between calcium carbonate (marble chips) and hydrochloric acid - AQA - GCSE Chemistry - Question 1 - 2015 - Paper 2
Step 1
State one conclusion the student could make about the effect of temperature on the rate of the reaction.
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Answer
The higher the temperature, the greater the rate of reaction.
Step 2
Give one reason why the student could make this conclusion.
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Answer
At higher temperatures, the reaction occurs faster, resulting in a quicker production of gas.
Step 3
For the hydrochloric acid at 60 °C the student had collected 30 cm³ after 15 seconds. Calculate the average rate of reaction from 0 to 15 seconds.
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Answer
The average rate of reaction is calculated using the formula:
extRate=TimeVolume of gas=15 seconds30 cm3=2 cm3/s
Step 4
Which two variables should the student keep constant? Tick (✓) two boxes.
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Answer
✓ Concentration of acid
✓ Mass of marble chips
Step 5
Explain, in terms of particles and collisions, the effect that increasing the surface area of the marble chips has on the rate of reaction.
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Answer
Increasing the surface area of marble chips increases the reaction rate because it allows more particles to collide with the hydrochloric acid. The more frequent collisions between particles lead to an increased likelihood of successful reactions.
Step 6
Give one reason why using a catalyst reduces costs.
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Answer
Using a catalyst increases the rate of reaction, which reduces the energy required to carry out the reaction, leading to lower production costs.
