Chemistry 9701/22 — October/November 2016

Cambridge AS Level · AS Level Structured Questions · worked solutions for every part, with the mark scheme

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Topics Introduction to Organic Chemistry · Atoms, Molecules and Stoichiometry · Chemical Energetics · States of Matter · Equilibria · Atomic Structure · +4 more

Q1Atoms, Molecules and StoichiometryFree sample

A $0.50\text{ g}$ sample of a Group 2 metal, M, was added to $40.0\text{ cm}^3$ of $1.00\text{ mol dm}^{-3}$ hydrochloric acid (an excess).

\text{equation 1} \quad \text{M(s)} + 2\text{HCl(aq)} \rightarrow \text{MCl}_2\text{(aq)} + \text{H}_2\text{(g)}

(a)

Calculate the amount, in moles, of hydrochloric acid present in $40.0\text{ cm}^3$ of $1.00\text{ mol dm}^{-3}$ $\text{HCl}$ .

(b)

When the reaction had finished, the resulting solution was made up to $100\text{ cm}^3$ in a volumetric flask.

A $10.0\text{ cm}^3$ sample of the solution from the volumetric flask required $15.0\text{ cm}^3$ of $0.050\text{ mol dm}^{-3}$ sodium carbonate solution, $\text{Na}_2\text{CO}_3$ , for complete neutralisation of the remaining hydrochloric acid.

(i)

Write the equation for the complete reaction of sodium carbonate with hydrochloric acid.

(ii)

Calculate the amount, in moles, of sodium carbonate needed to react with the hydrochloric acid in the $10.0\text{ cm}^3$ sample from the volumetric flask.

(iii)

Calculate the amount, in moles, of hydrochloric acid in the $10.0\text{ cm}^3$ sample.

(iv)

Calculate the total amount, in moles, of hydrochloric acid remaining after the reaction shown in equation 1.

(v)

Use your answers to (a) and (b)(iv) to calculate the amount, in moles, of hydrochloric acid that reacted with the $0.50\text{ g}$ sample of M.

(vi)

Use your answer to (v) and equation 1 to calculate the amount, in moles, of M in the $0.50\text{ g}$ sample.

(vii)

Calculate the relative atomic mass, $A_r$ , of M and identify M.

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4 more questions

Q2Chemical Energetics · States of Matter · Equilibria13M
Q3Atomic Structure · Chemical Periodicity15M
Q4Introduction to Organic Chemistry · Halogen Compounds17M
Q5Hydrocarbons · Introduction to Organic Chemistry · Carbonyl Compounds6M

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