Reactivity series lab answers for GCSE chemistry (free PDF download)

The method and the results are on the reactivity series lab. Do the analysis yourself first, then check the answers below.

Quick answer: The reactivity series ranks metals by how easily they lose electrons. These answers go with the Chemistry 9-10 lab on reactivity series: the graph, the calculations, the uncertainties and the conclusion explained, for all 8 analysis questions.

Reactivity series lab answers for GCSE chemistry (free PDF download)

The answers use the sample data. Your own temperatures will differ, but the order of the rises, the energy calculations and the explanations of the errors should follow the same pattern.

Level: Chemistry grades 9-10 (GCSE · IGCSE · O Level · Class 9-10) · Curriculum: GCSE C4

Contents

Question 1 Temperature rises

Magnesium 66.5 − 21.0 = 45.5 °C; zinc 42.5 − 21.0 = 21.5 °C; iron 36.0 − 21.0 = 15.0 °C; copper = 0.0 °C.

Question 2 Order of reactivity

The order of rise is Mg > Zn > Fe > Cu, so the order of reactivity is magnesium, zinc, iron, copper, which agrees with the series.

Question 3 Explain the copper result

Copper is the same metal as in the solution, so there is nothing to displace: no reaction occurs.

Question 4 Energy released

Q = 25.0 × 4.18 × 45.5 = 4755 J = 4.76 kJ.

Question 5 Energy per mole

Magnesium: 4.755 ÷ 0.0125 = 380 kJ/mol. Zinc: Q = 25.0 × 4.18 × 21.5 = 2247 J = 2.25 kJ, so 2.247 ÷ 0.0125 = 180 kJ/mol.

Question 6 Why excess metal

1.0 g of zinc is 1.0 ÷ 65 = 0.0154 mol, more than the 0.0125 mol of Cu²⁺, so zinc is in excess and all the copper ions are displaced.

Question 7 Errors

Heat is lost to the surroundings, so the rise is too small. Use a lid and an insulated cup, and stir gently so the thermometer reads the true maximum.

Question 8 Extending the lab

Aluminium is above zinc, so a large rise is expected, but its surface oxide layer can delay the reaction and the temperature may rise slowly.

← Back to the reactivity series lab

Reactivity order, top four metals? — Potassium, sodium, calcium, magnesium

Two non-metals in the series? — Carbon and hydrogen

Oxidation in terms of electrons? — Loss of electrons

Reduction in terms of oxygen? — Loss of oxygen

Extraction of metals above carbon? — Electrolysis of the molten compound

Extraction of iron? — Reduce iron oxide with carbon or CO

Blast furnace equation? — Fe₂O₃ + 3CO → 2Fe + 3CO₂

What is an ore? — Rock from which metal is profitably extracted

Displacement rule? — A more reactive metal displaces a less reactive one

Why zinc protects iron? — Zinc is more reactive and corrodes first