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A student investigated how a change in concentration affects the rate of the reaction between zinc powder and sulfuric acid - AQA - GCSE Chemistry - Question 9 - 2021 - Paper 2
Question 9
A student investigated how a change in concentration affects the rate of the reaction between zinc powder and sulfuric acid. The equation for the reaction is: Zn(s)... show full transcript
Worked Solution & Example Answer:A student investigated how a change in concentration affects the rate of the reaction between zinc powder and sulfuric acid - AQA - GCSE Chemistry - Question 9 - 2021 - Paper 2
Step 1
Step 2
Step 3
How does Figure 9 show that zinc powder reacts more slowly with 0.05 mol/dm³ sulfuric acid than with 0.10 mol/dm³ sulfuric acid?
Answer
The graph for 0.05 mol/dm³ sulfuric acid is less steep, indicating a slower rate of reaction. Additionally, the reaction using 0.05 mol/dm³ sulfuric acid takes longer to reach completion.
Step 4
Determine the rate of the reaction for 0.05 mol/dm³ sulfuric acid at 80 seconds.
Answer
To find the rate, draw a tangent at 80 seconds on the curve representing 0.05 mol/dm³. Calculate the gradient (rate) of this tangent using the formula:
ext{Rate} = rac{ ext{change in volume}}{ ext{change in time}}
Assuming the tangent line shows a change in volume of approximately 30 cm³ over a change in time of 30 seconds, the rate can be calculated as:
ext{Rate} = rac{30 ext{ cm}³}{30 ext{ s}} = 1 ext{ cm}³/s
Thus, the rate at 80 seconds is 1 cm³/s, given to 2 significant figures.
Step 5