Chemistry 5070 · O Level · Experimental design

Experimental design — practice question

In this experiment, a student changes magnesium into magnesium oxide, MgO. A 0.36 g portion of magnesium is heated strongly for several minutes with the apparatus shown.
(a)[2]

Identify apparatus A and B. A [BLANK] B [BLANK]

(b)[2]

Suggest one explanation for why the mass of MgO is less than expected and say how the expected result could be obtained.

(c)[2]

The student carries out a similar experiment using 0.36 g of zinc rather than 0.36 g of magnesium. Explain why it is incorrect to expect the mass of zinc oxide to be $0.60\text{ g}$ as well. $[A_r: \text{Mg}, 24; \text{Zn}, 65]$

(d)[1]

Suggest a safety item that the student should wear when carrying out this experiment.

Worked solution & mark scheme

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