Chemistry 9701 · AS & A Level · Atoms, molecules and stoichiometry

Atoms, molecules and stoichiometry — practice question

A neutralisation reaction takes place when $\text{NaOH(aq)}$ is added to $\text{H}_2\text{SO}_4\text{(aq)}$. Equation 1: $\text{2NaOH(aq)} + \text{H}_2\text{SO}_4\text{(aq)} \rightarrow \text{Na}_2\text{SO}_4\text{(aq)} + 2\text{H}_2\text{O(l)}$.
(a)[2]

State the definition of enthalpy change of neutralisation, $\Delta H_{\text{neut}}$.

(b(i))[1]

Use equation 1 to work out the amount, in mol, of $\text{H}_2\text{SO}_4\text{(aq)}$ neutralised in the experiment.

(b(ii))[3]

Calculate $\Delta H_{\text{neut}}$ from the data in Table 2.1. Include units in your answer. Assume the specific heat capacity of the final solution is $4.18\,\text{J g}^{-1}\text{K}^{-1}$, that $1.00\,\text{cm}^3$ of the final solution has a mass of $1.00\,\text{g}$, that no heat is lost to the surroundings, that $\text{H}_2\text{SO}_4\text{(aq)}$ fully dissociates, and that the experiment is carried out at constant pressure. Show your working.

(c(i))[2]

Complete the equation for the reaction when a solution of $\text{Ba(OH)}_2$ is added to aqueous sulfuric acid. Include state symbols.\n\n$\ldots\ldots\,\text{H}_2\text{SO}_4\text{(aq)} + \ldots\ldots\,\text{Ba(OH)}_2\text{(aq)} \rightarrow \ldots\ldots$

(c(ii))[1]

Explain why the enthalpy change of neutralisation cannot be found from adding dilute sulfuric acid to aqueous barium hydroxide.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: The enthalpy change when 1 mole of water is formed.

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