Chemistry 9701/23 — May/June 2021

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

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Topics Chemical Bonding · Equilibria · Atoms, Molecules and Stoichiometry · Introduction to Organic Chemistry · Hydroxy Compounds · Carboxylic Acids and Derivatives · +7 more

Q1Chemical BondingGroup 17EquilibriaAtoms, Molecules and StoichiometryElectrochemistryFree sample

The elements in Group 17 are known as the halogens.

(a)

Between the molecules of Group 17 elements van der Waals’ forces exist.

(i)

State the trend in the relative strength of van der Waals’ forces down Group 17.

(ii)

State the physical state of each of the halogens under room conditions.

chlorine ...............................................................................................................................

bromine ...............................................................................................................................

iodine ..................................................................................................................................

(b)

A solution of aqueous bromide ions, $\text{Br}^-(\text{aq})$ , is added to separate samples of $\text{Cl}_2(\text{aq})$ and $\text{I}_2(\text{aq})$ .

Describe what is observed in each reaction. Explain your answer in terms of the relative reactivity of these elements as oxidising agents.

observation on addition to $\text{Cl}_2(\text{aq})$ .............................................................................................

observation on addition to $\text{I}_2(\text{aq})$ ...............................................................................................

explanation ................................................................................................................................

(c)

Bleach is made by reacting $\text{Cl}_2$ with cold $\text{NaOH}(\text{aq})$ .

Write an equation for the reaction of $\text{Cl}_2$ with cold $\text{NaOH}$ .

(d)

When $\text{ClO}^-(\text{aq})$ is added to water, it behaves as a Brønsted-Lowry base.

(i)

Define the term Brønsted-Lowry base.

(ii)

Write an ionic equation for the reaction between $\text{ClO}^-$ and $\text{H}_2\text{O}$ .

(e)

The concentration of $\text{NaClO}$ in bleach S is $x\text{ g dm}^{-3}$ .

$\text{NaClO}$ reacts with $\text{H}_2\text{O}_2(\text{aq})$ as shown.

\text{H}_2\text{O}_2(\text{aq}) + \text{NaClO}(\text{aq}) \rightarrow \text{H}_2\text{O}(\text{l}) + \text{NaCl}(\text{aq}) + \text{O}_2(\text{g})

A $5.00\text{ cm}^3$ sample of S completely reacts with $\text{H}_2\text{O}_2(\text{aq})$ . The volume of $\text{O}_2(\text{g})$ produced is $24.0\text{ cm}^3$ under room conditions.

Assume that only the $\text{NaClO}$ in S reacts with $\text{H}_2\text{O}_2(\text{aq})$ .

Calculate $x$ . Show your working.

$x$ = .............................. $\text{g dm}^{-3}$

(f)

Sodium chlorate(I), $\text{NaClO}$ , oxidises dilute hydrochloric acid to form three products. The products which contain chlorine have chlorine species with oxidation number $-1$ or $0$ .

No other species changes its oxidation number during the reaction.

Use this information to complete the ionic equation.

........ $\text{ClO}^-$ + ...... $\text{HCl}$ $\rightarrow$ ............ + ............ + ............

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4 more questions

Q2Chemical Bonding · Equilibria14M
Q3Chemical Periodicity · Group IV (Group 14) · States of Matter · Atoms, Molecules and Stoichiometry11M
Q4Introduction to Organic Chemistry · Carbonyl Compounds · Hydroxy Compounds · Halogen Compounds · Carboxylic Acids and Derivatives12M
Q5Hydroxy Compounds · Carboxylic Acids and Derivatives · Introduction to Organic Chemistry10M

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