# A student wants to find out whether the type of metal affects how quickly it reacts with dilute sulfuric acid. The metals available are magnesium, zinc, and iron. Describe how the student should carry out a fair investigation to answer this question.

> Cambridge International IGCSE Chemistry (0620) — 12.1 Experimental design · Describe · 4 marks

## Mark scheme (4 marks)

1. Use the same volume (and concentration) of dilute sulfuric acid for each metal
2. Use the same mass (or size) of each metal
3. Measure the rate of reaction in a consistent way, e.g. measure the time taken for the metal to disappear / collect and measure the volume of hydrogen gas produced in a given time
4. Keep all other variables the same, e.g. temperature / room temperature, and repeat the experiment for each metal under the same conditions

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