Edexcel IGCSE Chemistry 3.3 Energy level diagrams

Practise using Q = mcΔT with solution volumes, masses and temperature changes to calculate heat energy transferred in reactions.

[Maximum number: 3]

A student investigates the reaction between zinc and copper(II) sulfate solution.
This is the equation for the reaction.

\mathrm{Zn}(\mathrm{~s})+\mathrm{CuSO}_{4}(\mathrm{aq}) \rightarrow \mathrm{ZnSO}_{4}(\mathrm{aq})+\mathrm{Cu}(\mathrm{~s})

This is the student's method.
Step 1 add $25.0 \mathrm{~cm}^{3}$ of copper(II) sulfate solution to a glass beaker
Step 2 record the temperature of the solution
Step 3 add between 5 g and 6 g of zinc powder (an excess) and stir the mixture
Step 4 record the highest temperature reached

The table shows the student's results.

Table for Question 3.3 Energy level diagrams question 1 — Edexcel IGCSE Chemistry

Calculate the heat energy change ( Q ) in joules (J).
[for the solution, $\mathrm{c}=4.2 \mathrm{~J} / \mathrm{g} /{ }^{\circ} \mathrm{C}$ ]
[mass of $1.0 \mathrm{~cm}^{3}$ of solution $=1.0 \mathrm{~g}$ ]

Q=\ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots . \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots . .

$\mathrm{M} 1 \Delta \mathrm{~T}=30.1\left({ }^{\circ} \mathrm{C}\right)$

M2 $25 \times 4.2 \times 30.1$

ALLOW ecf from M1

M3 3160.5(J)

ALLOW any number of
significant figures from
2

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3.3 Energy level diagrams question 1