AS & A Level Chemistry - 9701 Paper 1 2015 Summer Zone 3

The diagram shows the Boltzmann energy distribution curve for molecules of a mixture of two gases at a given temperature. For a reaction to occur the molecules must collide together with sufficient energy.
The graph is labeled with $E_{a1}$ and $E_{a2}$ on the x-axis, which represents molecular energy.
$E_a$ is used to represent the activation energy for the reaction between the gases. Of the two values shown, one is the activation energy for a catalysed reaction, the other for an uncatalysed reaction.
Which statement about $E_{a1}$ is correct?

Which diagram shows the correct graph of $pV$ against $n$ for an ideal gas at constant temperature?

A student performed an experiment to measure the enthalpy change of combustion of ethane.
He used the following values for the standard enthalpy changes of combustion of carbon and hydrogen.
\( \Delta H^\circ_c \text{carbon} = -394 \text{kJ mol}^{-1} \)
\( \Delta H^\circ_c \text{hydrogen} = -286 \text{kJ mol}^{-1} \)
He calculated the enthalpy change of formation of ethane to be \(-140 \text{kJ mol}^{-1}\).
What was his experimental value for the standard enthalpy change of combustion of ethane?

Which pair has species with different shapes?

In which reaction does an element have the largest change in oxidation number?

Which statement can be explained by intermolecular hydrogen bonding?

Carbon monoxide and methanol can react together to form ethanoic acid.
$$ \text{CO(g)} + \text{CH}_3\text{OH(l)} \rightarrow \text{CH}_3\text{CO}_2\text{H(l)} $$
Standard enthalpy changes of combustion are given in the table.
[Table_1]
What is the value for $\Delta H_r^\circ$ for the reaction between carbon monoxide and methanol?

The following reaction was carried out.
$$\text{HCO}_2\text{CH}_3(aq) + \text{NaOH}(aq) \rightarrow \text{HCO}_2\text{Na}(aq) + \text{CH}_3\text{OH}(aq)$$
The concentration of methanol, $[\text{CH}_3\text{OH}(aq)]$, was measured with time, $t$.
Which graph shows the relationship between $[\text{CH}_3\text{OH}(aq)]$ and $t$?

Brine is concentrated aqueous sodium chloride. Brine is electrolysed in a diaphragm cell.
What is the purpose of the diaphragm?

Use of the Data Booklet is relevant to this question.
1.00 g of a metallic element reacts completely with 300 cm^3 of oxygen at 298 K and 1 atm pressure to form an oxide which contains $O^{2-}$ ions.
The volume of one mole of gas at this temperature and pressure is 24.0 dm^3.
What could be the identity of the metal?

Use of the Data Booklet is relevant to this question.
The gas laws can be summarised in the ideal gas equation below.
$$ pV = nRT $$
When an evacuated tube of volume 400 cm³ is filled with gas at 300 K and 101 kPa, the mass of the tube increases by 0.65 g.
Assume the gas behaves as an ideal gas.
What could be the identity of the gas?

Which oxide will produce the solution with the highest pH when it is mixed with water?

Barium is a more reactive metal than aluminium. Which method could be suitable for the extraction of barium?

The compound $(CH_3)_3NAICl_3$ has a simple molecular structure.
Which statement about $(CH_3)_3NAICl_3$ is correct?

The labels had become detached from four bottles in the laboratory. A student realised that the contents of one of them could easily be identified, because on addition of water it would not give fumes of hydrogen chloride.
Which did not give the HCl fumes?

Transition elements and their compounds are widely used as catalysts.
What is the identity and what is the oxidation number of the element present in the catalyst used in the Contact process?
[Table_1]

This question refers to isolated gaseous species.
The species $\text{F}^-$, Ne, and $\text{Na}^+$ are isoelectronic. This means they have the same number of electrons.
In which order do their radii increase?
[Table_1]

Due to their similar ionic radii, the reactions of lithium and magnesium and their corresponding compounds are very similar.
Which statement about the reactions of lithium or its compounds can be predicted from this statement?

Two separate tests were carried out on an aqueous solution of a salt which contains only two ions.
In each test, the resulting mixtures were filtered and the filtrate solution was collected.

\begin{array}{|c|c|c|} \hline \text{reagent} & \text{result} & \text{filtrate collected} \\ \hline \text{test 1} & \text{aqueous silver nitrate acidified with dilute nitric acid} & \text{yellow precipitate forms}\, \text{solution P} \\ \text{test 2} & \text{dilute sulfuric acid} & \text{white precipitate forms}\, \text{solution Q} \\ \hline \end{array}

Which ions are present in the filtrates?

An organic compound $Z$
• is oxidised by hot acidified potassium manganate(VII),
• reacts with sodium to give hydrogen.
What could be compound $Z$?

The diagram shows a molecule that has $\sigma$ bonds and $\pi$ bonds.

How many $\sigma$ bonds are present in this molecule?

The Finkelstein reaction occurs when NaI in propanone reacts with a chloroalkane or bromoalkane. The halogen is directly replaced by I and the reaction only works for primary halogenoalkanes.
Which halogenoalkane would produce compound X?

An ester P with a fruity odour has the following structural formula.

Which compounds are produced when P is hydrolysed using hydrochloric acid?

The naturally-occurring molecule civetone is found in a gland of the African civet cat and has been used in perfumery. Which reagent will not react with civetone?

Compound $X$, $C_5H_{12}O$, is oxidised by acidified sodium dichromate(VI) to compound $Y$.
Compound $Y$ reacts with butan-2-ol in the presence of a little concentrated sulfuric acid to give liquid $Z$.
What could be the formula of $Z$?

Alkane X has molecular formula $C_4H_{10}$.
X reacts with $Cl_2(g)$ in the presence of sunlight to produce only two different monochloroalkanes, $C_4H_9Cl$. Both of these monochloroalkanes produce the same alkene Y, and no other organic products, when they are treated with hot ethanolic KOH.

What is produced when Y is treated with hot concentrated acidified $KMnO_4$?

The compound aspartame is widely used as a sweetener in ‘diet’ soft drinks.

Aspartame is chiral. (There are no chiral carbon atoms in $C_6H_5$.)

How many chiral carbon atoms are present in a molecule of aspartame?

A tertiary bromoalkane, indicated here by $\text{>C–Br}$, reacts with aqueous NaOH. The mechanism has the reaction pathway below.

Which point in the diagram is correctly identified?

Four drops of 1-chlorobutane, 1-bromobutane and 1-iodobutane were put separately into three test-tubes containing 1.0 \text{ cm}^3 of aqueous silver nitrate at 60\degree C.
In each case, a hydrolysis reaction occurred. R represents the butane chain C_4H_9 and X the halogen atom.
$$ \text{H}_2\text{O(l)} + \text{R--X(l)} + \text{Ag}^+\text{(aq)} \rightarrow \text{R--OH(aq)} + \text{AgX(s)} + \text{H}^+\text{(aq)} $$
The rate of formation of cloudiness in the test-tubes was in the order RCl < RBr < RI.
Why is this?

Malic acid occurs in apples.
Under suitable conditions, which substance will react with only one of the –OH groups in the malic acid molecule?

The technetium-99 isotope, \(^{99}\text{Tc}\), is radioactive and has been found in lobsters and seaweed near to nuclear fuel reprocessing plants.
Which statements about an atom of \(^{99}\text{Tc}\) are correct?
1. It has 13 fewer protons than neutrons.
2. It forms \(^{99}\text{Tc}^{2+}\) which has 45 electrons.
3. It has 56 nucleons.

Nitrogen exists in air as covalently bonded diatomic molecules, N_2.
Which features are present in one N_2 molecule?

When dilute acid is added to an aqueous solution containing nitrite ions, NO_2^-, a mixture of gases is produced.

$$2H^+(aq) + 2NO_2^-(aq) \rightarrow H_2O(l) + NO(g) + NO_2(g)$$

Which statements correctly describe the process?
1. Some nitrogen atoms are oxidised and some nitrogen atoms are reduced.
2. The $H^+(aq)$ ion is oxidised by $NO_2^-(aq)$.
3. The $H^+(aq)$ ion acts as a catalyst.

Which physical properties are due to hydrogen bonding between water molecules?
1. Water has a higher boiling point than H$_2$S.
2. Ice floats on water.
3. The H–O–H bond angle in water is approximately 104°.

Under atmospheric conditions, in which transformations is sulfur dioxide involved as either a reagent or a catalyst?
1. $\text{NO}_2$ to NO
2. NO to $\text{NO}_2$
3. CO to $\text{CO}_2$

The element astatine, At, is below iodine in Group VII of the Periodic Table.
Which statements concerning At can be predicted to be correct?
1. At_2 reacts with hydrogen more slowly than I_2 does.
2. $\text{At}^{-}$ ions react with $\text{I}_2(\text{aq})$ to form $\text{At}_2$ molecules.
3. $\text{At}_2$ is a dark coloured solid at room temperature.

The diagram shows a molecule of a compound used as a flame retardant.

Which statements about this structure are correct?
1. Each brominated C atom is chiral.
2. The molecular formula is $C_{12}H_{20}Br_{6}$.
3. The C–C–C bond angles are all 120°.

Which changes in bonding occur during the reaction of propanal and hydrogen cyanide?
1. A carbon-hydrogen bond is broken.
2. An oxygen-hydrogen bond is formed.
3. A carbon-carbon bond is formed.

Which pairs of reagents will react together in a redox reaction?
1. $ \text{CH}_3\text{CHO} + \text{Fehling’s reagent} $
2. $ \text{C}_2\text{H}_4 + \text{Br}_2(\text{aq}) $
3. $ \text{CH}_4 + \text{Cl}_2(\text{g}) $

Which types of reaction are undergone by $\text{CH}_2\text{BrCHCH}_2$?