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This question is about the rate of reaction between calcium carbonate and dilute hydrochloric acid - Edexcel - GCSE Chemistry Combined Science - Question 4 - 2021 - Paper 1
Question 4
This question is about the rate of reaction between calcium carbonate and dilute hydrochloric acid. The word equation for this reaction is calcium carbonate + hydr... show full transcript
Worked Solution & Example Answer:This question is about the rate of reaction between calcium carbonate and dilute hydrochloric acid - Edexcel - GCSE Chemistry Combined Science - Question 4 - 2021 - Paper 1
Step 1
Step 2
Complete the diagram in Figure 5 to show the apparatus to collect the gas produced and measure its volume.
Answer
The diagram should include a delivery tube connected to the conical flask, which has the calcium carbonate and dilute hydrochloric acid mixture. The other end of the delivery tube should lead to a gas syringe or an upturned measuring cylinder in water, allowing for accurate measurement of the gas volume produced.
Step 3
State what could be used to keep the temperature of the conical flask and its contents at a temperature of 45 °C throughout the reaction.
Answer
A water bath set to a constant temperature of 45 °C could be used to maintain the temperature of the conical flask and its contents throughout the reaction.
Step 4
Draw a tangent at 100 seconds on Figure 6. Use this tangent to calculate the rate of reaction at this time.
Answer
To calculate the rate of reaction at 100 seconds, draw a tangent line on the graph at the point where time is 100 seconds. Determine the slope of this tangent line, which represents the change in volume of gas collected over the change in time. The rate of reaction can be calculated as the change in volume (in cm³) divided by the change in time (in seconds).
Step 5
Step 6
Explain, in terms of particles, how decreasing the temperature affects the rate of this reaction.
Answer
Decreasing the temperature reduces the kinetic energy of the particles in the reactants. As a result, the particles move slower, leading to fewer collisions between them over a given time period. This decrease in collision frequency reduces the likelihood of successful collisions that result in a reaction, thereby slowing down the overall rate of the reaction.