AS & A Level Chemistry - 9701 Paper 1 2014 Summer Zone 3

The Boltzmann distribution for a gas at constant temperature is shown below.
If the temperature of the gas is reduced by 10°C the graph changes shape.
What happens to the values of $n$ for the molecular energies X, Y and Z?

Which compound has the greatest total number of lone pairs of electrons in the valence shells of all of its atoms?

A reaction pathway diagram is shown.
Which enthalpy change could the diagram not apply to?

Use of the Data Booklet is relevant to this question.
The most common ion-molecule reaction in gas clouds of the Universe is as shown.
$$\text{H}_2(g) + \text{H}_2^+(g) \rightarrow \text{H}(g) + \text{H}_3^+(g)$$
What could be the composition of an H₃⁺ ion?
[Table_1]

The electrolysis of brine using the diaphragm cell is an important industrial process. What happens at the anode?

Hydrazine, $\text{N}_2\text{H}_4$, is used as a rocket fuel because it reacts with oxygen as shown, producing 'environmentally friendly' gases.

$\text{N}_2\text{H}_4(l) + \text{O}_2(g) \rightarrow \text{N}_2(g) + 2\text{H}_2\text{O}(g) \quad \Delta H = -534 \text{kJ mol}^{-1}$

Despite its use as a rocket fuel, hydrazine does not burn spontaneously in oxygen.

Which statement explains why hydrazine does \textit{not} burn spontaneously?

A 10.0 cm^3 bubble of an ideal gas is formed on the sea bed where it is at a pressure of 2020 kPa. Just below the sea surface the pressure is 101 kPa and the temperature is the same as the sea bed. What is the volume of the bubble when it rises to just below the sea surface?

Four substances have the physical properties shown in [Table_1].
Which substance is an ionic solid?

The enthalpy change of formation of $\text{Mn(NO}_3)_2(\text{s})$ is $-696\text{ kJ mol}^{-1}$.
The enthalpy change of formation of $\text{MnO}_2(\text{s})$ is $-520\text{ kJ mol}^{-1}$.
The enthalpy change of formation of $\text{NO}_2(\text{g})$ is $+33\text{ kJ mol}^{-1}$.

On heating, $\text{Mn(NO}_3)_2$ decomposes into $\text{MnO}_2$ and $\text{NO}_2$.

$\text{Mn(NO}_3)_2(\text{s}) \rightarrow \text{MnO}_2(\text{s}) + 2\text{NO}_2(\text{g})$

What is the value of the standard enthalpy change of this reaction?

X is an element in Period 2. In which fluoride is the F−X−F angle the largest?

Which reaction has an enthalpy change equal to the standard enthalpy change of formation of propane?

A student investigated the chloride of a Period 3 element. This is what he wrote down as his record of what he did and what he saw.

What can be deduced from this record?

X is an s-block element. X forms an insoluble carbonate with the formula $XCO_3$. X forms a hydroxide that is more soluble than strontium hydroxide. What could be the identity of X?

Which graph correctly shows the melting points of the elements Mg, Al, Si and P plotted against their first ionisation energies?

Which substance will not be a product of the thermal decomposition of hydrated magnesium nitrate?

The species Ne, Na^+ and Mg^{2+} are isoelectronic. This means that they have the same number of electrons. In which order do their radii increase? [Table_1]

Use of the Data Booklet is relevant to this question.
In an experiment, 0.6 mol of chlorine gas, $Cl_2$, is reacted with an excess of hot aqueous sodium hydroxide. One of the products is a compound of sodium, oxygen, and chlorine.
Which mass of this product is formed?

Which properties do compounds of aluminium and silicon have in common?

When strontium is burnt in oxygen, what colour is the flame?

Diesters can be made from diacids such as propane-1,3-dioic acid, $HO_2CCH_2CO_2H$.
Which combination of reactants would form the diester $CH_3CH_2OCOCH_2CH_2CO_2CH_2CH_3$?

In the presence of ultraviolet light, ethane and chlorine react to give a mixture of products. Which compound could be present in the mixture of products?

Compound X produces a carboxylic acid when heated under reflux with acidified potassium dichromate(VI). Compound X has no reaction with sodium metal.
What could be the identity of compound X?

Which molecule could not be obtained from the cracking of a molecule of nonane, CH_3(CH_2)_7CH_3?

A student investigates four different fuels. Each fuel is used separately to raise the temperature of 1 dm$^3$ of water from 20°C to 100°C. Each fuel undergoes complete combustion. All other conditions are the same in each experiment.
Which fuel would produce the smallest amount of carbon dioxide in these experiments?
[Table_1]

Most alcohols can be dehydrated to give alkenes. Which alcohol can be dehydrated to give three different isomeric alkenes?

Hept-4-enal is present in cow’s milk.

$$\text{CH}_3\text{CH}_2\text{CH}=\text{CHCH}_2\text{CH}_2\text{CHO}$$
hept-4-enal

Which row correctly shows the product formed when hept-4-enal is treated with the given reducing agent?

[Table_1]

The naturally-occurring molecule shown below can be made by the addition of four identical monomer molecules.
What could be the structural formula of the monomer?

The compound cetyl palmitate, $C_{15}H_{31}CO_2C_{16}H_{33}$, is a waxy solid.
When cetyl palmitate is heated under reflux with an excess of aqueous sodium hydroxide, which products will be formed?

One reaction in the Krebs cycle, in which energy is released to the human body, is the conversion of fumaric acid into malic acid.
\[\text{HO}_2\text{CCH}=\text{CHCO}_2\text{H} \rightarrow \text{HO}_2\text{CCH(OH)CH}_2\text{CO}_2\text{H}\]
fumaric acid malic acid
Which reagent(s) could achieve this conversion in the laboratory?

The free radical substitution reaction between methane and chlorine involves initiation, propagation and termination stages.
Which row is correct?
[Table_1]

For each of the questions in this section, one or more of the three numbered statements 1 to 3 may be correct.
Decide whether each of the statements is or is not correct (you may find it helpful to put a tick against the statements that you consider to be correct).
The responses A to D should be selected on the basis of
[Table_1]
No other combination of statements is used as a correct response.
In 2011 an international group of scientists agreed to add two new elements to the Periodic Table. Both elements had been made artificially and were called ununquadium (Uuq) and ununhexium (Uuh).
[Table_2]
Which statements about these elements are correct?
1. One atom of Uuh has one more neutron than one atom of Uuq.
2. One Uuq^{2-} ion has the same number of electrons as one atom of Uuh.
3. One Uuh^{+} ion has the same number of electrons as one Uuq^{-} ion.

P and Q are two liquid compounds with similar $M_r$ values. Molecules of P attract each other by hydrogen bonds. Molecules of Q attract each other by van der Waals' forces only.
How do the properties of P and Q differ?
1. P has higher surface tension than Q.
2. P has a higher boiling point than Q.
3. P is less viscous than Q.

Many crude oils contain H₂S. During refining, by the Claus process, the H₂S is converted into solid sulfur, which is then removed.

reaction I: $2\text{H}_2\text{S(g)} + 3\text{O}_2\text{(g)} \rightarrow 2\text{H}_2\text{O(l)} + 2\text{SO}_2\text{(g)}$
reaction II: $2\text{H}_2\text{S(g)} + \text{SO}_2\text{(g)} \rightarrow 2\text{H}_2\text{O(l)} + 3\text{S(s)}$

Which statements about the Claus process are correct?
1. H₂S is oxidised in reaction I.
2. SO₂ oxidises H₂S in reaction II.
3. Hydrogen is oxidised in reaction II.

The stoichiometry of a catalysed reaction is shown by the equation below.

$P(g) + Q(g) \rightleftharpoons R(g) + S(l)$

Two experiments were carried out in which the rate of production of $R$ was measured. The results are shown in the diagram below.



Which changes in the conditions might explain the results shown?

Which statements explain why sulfur dioxide is used as a food preservative?
1. It is a reducing agent and therefore an anti-oxidant.
2. It prevents alcohols in foods forming sour-tasting acids.
3. It does not smell and therefore can be used in large quantities.

The intermolecular forces between iodine molecules are instantaneous dipole-induced dipole forces.
Which statements explain why iodine has these intermolecular forces?

1. An iodine molecule is polar and experiences an attraction from a lone pair of electrons on an adjacent molecule.
2. An iodine molecule has a fluctuating dipole because the electrons in a molecule are more mobile than the nuclei.
3. The electron charge cloud within an $I_2$ molecule may become unsymmetrical and may then attract other $I_2$ molecules.

Which reactions must be warmed to form a solid product?
1. $\text{CH}_3\text{CH}_2\text{CHO} + 2,4\text{-dinitrophenylhydrazine reagent}$
2. $\text{CH}_3\text{CH}_2\text{CHO} + \text{Fehling's reagent}$
3. $\text{CH}_3\text{CH}_2\text{CHO} + \text{Tollens' reagent}$

When hydrolysed with dilute sulfuric acid, which compounds produce propanoic acid?
1. $\text{CH}_3\text{CH}_2\text{CO}_2\text{CH}_3$
2. $\text{CH}_3\text{CH}_2\text{CH}_2\text{CN}$
3. $\text{CH}_3\text{CH}_2\text{CH}_2\text{Cl}$

Propane-1,2,3-triol is the raw material for many important industrial chemical processes.
[Image_1: Structure of propane-1,2,3-triol]
Which statements about propane-1,2,3-triol are correct?
1. It reacts with carboxylic acids to form compounds containing up to three ester groups.
2. It can be oxidised to form compounds with aldehyde and ketone functional groups.
3. It can be oxidised to form compounds with up to three carboxylic acid groups.

The diagram shows an experimental set-up which can be used in several different experiments.

Which processes could be demonstrated by using the above apparatus?
1. oxidation of ethanol (liquid X)
2. dehydration of ethanol (liquid X)
3. cracking of paraffin (liquid X)