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This question is about magnesium - AQA - GCSE Chemistry Combined Science - Question 5 - 2019 - Paper 2
Question 5
This question is about magnesium. A student investigated the rate of the reaction between magnesium and hydrochloric acid. Figure 2 shows the apparatus. Figure 2 ... show full transcript
Worked Solution & Example Answer:This question is about magnesium - AQA - GCSE Chemistry Combined Science - Question 5 - 2019 - Paper 2
Step 1
Step 2
Step 3
Plot the data from Table 2 on Figure 3.
Answer
To plot the data:
- Mark the time in seconds on the x-axis.
- Mark the volume of gas produced in cm³ on the y-axis.
- Plot the corresponding points based on Table 2. After plotting, draw a line of best fit, showing the trend of the reaction rate over time.
Step 4
Describe the changes in the rate of this reaction.
Answer
The rate of the reaction decreases over time. Initially, the rate is fastest as magnesium reacts with hydrochloric acid, producing gas rapidly. As the reaction progresses, the decrease in unreacted magnesium leads to a slower production of gas. Eventually, the reaction may cease when no magnesium is left.
Step 5
Explain why the rate of this reaction changes.
Answer
The rate decreases because fewer particles of hydrochloric acid are available as the reaction proceeds. Fewer reactant particles result in less frequent collisions between magnesium and hydrochloric acid, leading to a reduced reaction rate. Additionally, the reaction may eventually stop due to limiting factor/reagent, as the magnesium is consumed.