Chemistry Practice Exam Paper 2 06
Magnesium reacts with dilute hydrochloric acid: Mg(s) + 2HCl(aq)
MgCl2(aq) + H2(g)
A student investigated how the volume of hydrogen produced over time changes when magnesium is reacted with two different concentrations of dilute hydrochloric acid. This is the method used: 1. Measure 20 cm3 of 0.5 mol/dm3 hydrochloric acid using a measuring cylinder. 2. Pour the acid into the conical flask. 3. Add 2 g of magnesium strip. 4. Place the bung into the flask. 5. Measure the volume of gas every 30 seconds until the reaction is complete. 6. Repeat using 1 mol/dm3 hydrochloric acid. The student reached the end of Step 2 and set up the apparatus as shown in Figure 2. Figure 2
06.1 Identify what the student should do before continuing with the method. Describe what could happen if the student continued without making any changes. Explain how this would affect the results.
[3 marks]
Question 6 continues on the next page
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GCSE Combined Science Workbook
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6/29/16 12:32 PM