AS & A Level Chemistry - 9701 Paper 1 2014 Winter Zone 2

Which solid-line curve most accurately represents the distribution of molecular energies in a gas at 500K if the dotted-line curve represents the corresponding distribution for the same gas at 300K?

In which reaction does hydrogen behave as an oxidising agent?

Ethanol is increasingly being used as a fuel for cars.
The standard enthalpy change of formation of carbon dioxide is $-393\text{ kJ mol}^{-1}$.
The standard enthalpy change of formation of water is $-286\text{ kJ mol}^{-1}$.
The standard enthalpy change of formation of ethanol is $-277\text{ kJ mol}^{-1}$.
What is the standard enthalpy change of combustion of ethanol?

Two glass vessels M and N are connected by a closed valve.
M contains helium at 20°C at a pressure of $1 \times 10^5$ Pa. N has been evacuated, and has three times the volume of M. In an experiment, the valve is opened and the temperature of the whole apparatus is raised to 100°C.
What is the final pressure in the system?

The table shows the physical properties of four substances. Which substance could be hydrogen chloride?
[Table_1]

Aluminium carbide, $\text{Al}_{4}\text{C}_{3}$, reacts readily with aqueous sodium hydroxide. The two products of the reaction are $\text{NaAlO}_{2}$ and a hydrocarbon. Water molecules are also involved as reactants.
What is the formula of the hydrocarbon?

In an experiment to calculate the enthalpy change of combustion of a fuel, 1.5 g (0.0326 mol) of the fuel was used to heat 200 g of water. The temperature of the water rose from 25°C to 55°C. The specific heat capacity of water is 4.18 J g$^{-1}$ K$^{-1}$.
There is significant heat loss in this experiment. Therefore, the experimental value for the enthalpy change of combustion, $\Delta H_c$, of the fuel will be different from the theoretical value.
Using the information above, what is the experimental value for the enthalpy change of combustion, $\Delta H_c$, of the fuel?

The reaction pathway diagram below illustrates the energies of the reactants, the products and the transition state of a reaction.

Which expression represents the activation energy of the forward reaction?

Methylpropan-1-ol and butan-1-ol are structural isomers. Methylpropan-1-ol has a lower boiling point.
Which statement explains why the boiling point of methylpropan-1-ol is lower than that of butan-1-ol?

Which row correctly describes the electrodes used in the electrolysis cell for the production of aluminium? [Table_1]

For which equation is the enthalpy change correctly described as an enthalpy change of formation?

Element $X$, in Period 3, has the following properties:
• Its oxide has a giant structure.
• It forms covalent bonds with chlorine.
• Its oxide will neutralise $HCl_{(aq)}$.
What is element $X$?

Which property is not associated with the element sodium?

Use of the Data Booklet is relevant to this question.
Sir Humphrey Davy discovered boron, calcium, magnesium and sodium.
Which of these elements has the second smallest atomic radius in its group and the third lowest first ionisation energy in its period?

Use of the Data Booklet is relevant to this question.
A sample of potassium oxide, $K_2O$, is dissolved in $250 ext{ cm}^3$ of distilled water. $25.0 ext{ cm}^3$ of this solution is titrated against sulfuric acid of concentration $2.00 ext{ mol dm}^{-3}$. $15.0 ext{ cm}^3$ of this sulfuric acid is needed for complete neutralisation.
Which mass of potassium oxide was originally dissolved in $250 ext{ cm}^3$ of distilled water?

Chlorine gas reacts with cold aqueous sodium hydroxide. It can also react with hot aqueous sodium hydroxide.

What are the oxidation numbers of chlorine in the products of these reactions?
[Table_1]

Under standard conditions, which statement is correct?

Total removal of the pollutant sulfur dioxide, $SO_2$, is difficult. The quantities emitted from furnace chimneys can be lowered by using desulfurisation plants. The gases are reacted with calcium hydroxide to remove the $SO_2$.
What is the main product formed initially?

Which oxide does not react with cold dilute sodium hydroxide to produce a salt?

Which row correctly describes the reaction between propene and bromine, $Br_2(l)$? [Table_1]

Use of the Data Booklet is relevant to this question.
Which compound has an $M_r$ of 84 and will react with HBr to give a product with an $M_r$ of 164.9?

1,1-dichloropropane reacts with aqueous sodium hydroxide in a series of steps to give propanal.
$$\text{CH}_3\text{CH}_2\text{CHCl}_2 \xrightarrow{\text{NaOH(aq)}} \text{CH}_3\text{CH}_2\text{CHO}$$
Which term describes the first step of this reaction?

Considering only structural isomers, what is the number of alcohols of each type with the formula $C_5H_{12}O$?
[Table_1]

Lactic acid, CH$_3$CH(OH)CO$_2$H, causes pain when it builds up in muscles.
Which reagent reacts with both of the −OH groups in lactic acid?

In the hydrolysis of bromoethane by aqueous sodium hydroxide, what is the nature of the attacking group and of the leaving group?
[Table_1: Attacking group and leaving group options]

Corticosterone is a hormone involved in the metabolism of carbohydrates and proteins.
How many chiral centres are there in one molecule of corticosterone?

Methyl methylpropenoate is the monomer used to make Perspex. Which diagram correctly shows methyl methylpropenoate?

The ester CH$_3$CH$_2$CH$_2$CO$_2$CH$_3$ is responsible for the aroma of apples.
When this ester is hydrolysed by acid in the stomach, what is the empirical formula of the organic acid produced?

Which equation correctly represents the balanced equation for the complete combustion of a hydrocarbon with the formula $C_xH_y$?

β-carotene is responsible for the orange colour of carrots.

β-carotene is oxidised by hot, concentrated, acidified KMnO₄.
When an individual molecule of β-carotene is oxidised in this way, many product molecules are formed.
How many of these product molecules contain a ketone functional group?

Which ions contain one or more unpaired electrons?
1. Cu$^{2+}$
2. Mn$^{3+}$
3. V$^{3+}$

Use of the Data Booklet is relevant to this question.
The bond energy of the $\text{Br} - \text{O}$ bond is $235\, \text{kJ mol}^{-1}$.
Which reactions are exothermic?
1. $\text{OH}^\bullet + \text{HBr} \rightarrow \text{H}_2 + \text{BrO}^\bullet$
2. $\text{OH}^\bullet + \text{HBr} \rightarrow \text{H}_2\text{O} + \text{Br}^\bullet$
3. $\text{H}^\bullet + \text{HBr} \rightarrow \text{H}_2 + \text{Br}^\bullet$

Which statements about the effects of the catalyst on this system are correct?
1. The catalyst alters the mechanism of the reaction.
2. The catalyst reduces the activation energy for both the forward and the backward reaction.
3. The catalyst alters the composition of the equilibrium mixture.

A student borrowed a friend’s chemistry notes and copied out the notes in the box below.
Which statements are correct?
[Table_1: Table shows options of correctness]
A gas behaves less like an ideal gas when the gas
1 is at low pressure.
2 is at low temperature.
3 can be easily liquefied.

On being heated, hydrogen iodide breaks down more quickly than hydrogen chloride. Which statements explain this faster rate?
1. The HI bond is weaker than the HCl bond.
2. The reaction of the breakdown of HI has a smaller activation energy than that of HCl.
3. The breakdown of HI is more exothermic than that of HCl.

Which statements about calcium oxide are correct?
1. It reacts with cold water.
2. It is produced when calcium nitrate is heated.
3. It can be reduced by heating with magnesium.

Propanal will react with hydrogen cyanide to form 2-hydroxybutanenitrile. A suitable catalyst for this reaction is sodium cyanide.

Which statements about the reaction of propanal with hydrogen cyanide are correct?

1. The $\text{CN}^-$ ion attacks the propanal molecule to form an intermediate ion.
2. The product of the reaction has a chiral carbon atom.
3. The $\text{CN}^-$ ion is a stronger electrophile than the HCN molecule.

X is an organic compound that gives a precipitate with aqueous silver nitrate. This precipitate remains undissolved when concentrated aqueous ammonia is added. What is a possible identity for X?

For which mixtures of reagents are the colour changes described correctly?
[Table_1]

A reaction pathway diagram is shown.

Which reactions would have this profile?
1. $(CH_3)_3CBr + NaOH \rightarrow (CH_3)_3COH + NaBr$
2. $CH_3CH_2Br + NaOH \rightarrow CH_3CH_2OH + NaBr$
3. $(CH_3)_3CCH_2CH_2Cl + 2NH_3 \rightarrow (CH_3)_3CCH_2CH_2NH_2 + NH_4Cl$