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 finishes sooner, indicating a faster rate.
Step 3
Calculate the average rate of reaction from 0 to 15 seconds.
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Answer
The average rate of reaction can be calculated using the formula:
Average rate = ( \frac{\text{Volume of gas}}{\text{Time}} = \frac{30 \text{ cm}³}{15 \text{ s}} = 2 \text{ cm}³/s )
Step 4
Which two variables should the student keep constant? Tick (✓) two boxes.
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Answer
The student should keep the following two variables constant:
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 the marble chips increases the rate of reaction because it allows more particles to be exposed and available for collision, leading to more frequent collisions between reactant particles.
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 means less time and energy are required for the process.
