AS & A Level Chemistry - 9701 Paper 1 2019 Summer Zone 1

The temperature of a sample of an inert gas is increased.
What effect does this have on the number of molecules with the most probable energy and on the number of molecules with high energy?
[Table_1]

A sample of element X is analysed using mass spectrometry. The mass spectrum obtained is shown.

What is the relative atomic mass of this sample of element X?

A washing powder contains sodium hydrogencarbonate, NaHCO_3, as one of the ingredients.
In a titration, a solution containing 1.00 g of this washing powder requires 7.15 cm^3 of 0.100 mol dm^{-3} sulfuric acid for complete reaction. The sodium hydrogencarbonate is the only ingredient that reacts with the acid.
What is the percentage by mass of sodium hydrogencarbonate in the washing powder?

The outermost electron in an atom of neon occupies a particular orbital.
Which row shows the relative energy and shape of this orbital?
[Table_1: Energy and shape of orbital]

In which species is there a lone pair of electrons?

When an evacuated tube of volume 400 cm$^3$ 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?

Under which conditions will nitrogen behave most like an ideal gas?
[Table with conditions]

Two reactions and their enthalpy changes are shown.

2C(s) + 2H$_2$(g) \rightarrow C$_2$H$_4$(g) \hspace{1em} \Delta H^\circ = +52.2 \text{ kJ mol}^{-1}
C$_2$H$_2$(g) + H$_2$(g) \rightarrow C$_2$H$_4$(g) \hspace{1em} \Delta H^\circ = -175.8 \text{ kJ mol}^{-1}

These data can be used to calculate the enthalpy change for the reaction shown.

2C(s) + H$_2$(g) \rightarrow C$_2$H$_2$(g) \hspace{1em} \Delta H^\circ = X

What is the value of X?

Ethandioic acid, HO$_2$CCO$_2$H, can be oxidised by KMnO$_4$ in dilute sulfuric acid. The products of this reaction are carbon dioxide, water, potassium sulfate and manganese(II) sulfate.

In this reaction each ethanedioic acid molecule loses two electrons as it is oxidised. A half-equation for this process is shown.

HO$_2$CCO$_2$H $ \rightarrow $ 2CO$_2$ + 2H$^+$ + 2e$^-$

How many water molecules are produced when five ethanedioic acid molecules are oxidised by KMnO$_4$ in dilute sulfuric acid?

Hydrogen iodide gas decomposes reversibly producing iodine vapour and hydrogen.
$$2HI(g) \rightleftharpoons I_2(g) + H_2(g) \quad \Delta H = +12 \text{ kJ mol}^{-1}$$
The position of the equilibrium for this reaction may be altered by changing the external conditions.
Which row correctly describes the change in position of equilibrium?
[Table_1]

The reaction between sulfur dioxide and oxygen is reversible.

$$2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g) \quad K_c = 280 \text{ mol}^{-1}\text{dm}^3 \text{ at } 1000K$$

In an equilibrium mixture at 1000 K the sulfur trioxide concentration is 6.00 mol dm^-3.
The sulfur dioxide concentration is twice the oxygen concentration.

What is the sulfur dioxide concentration?

1. 1.15 g of a metallic element needs 300 cm³ of oxygen for complete reaction, under room conditions, to form an oxide which contains $O^{2-}$ ions. What could be the identity of this metallic element?

The relative melting points of four consecutive elements in the Periodic Table are shown in the graph.
The elements all have proton numbers less than 20. Which element is in Group 16?
[Image_1: Graph showing relative melting points]

Substance X reacts with water. A gas is given off and the pH of the solution increases. The solution is then reacted with sulfuric acid and a white precipitate forms. What could be substance X?

Solutions of $0.1 \, \text{mol} \, \text{dm}^{-3}$ $\text{Mg(NO}_3)_2$ and $0.1 \, \text{mol} \, \text{dm}^{-3}$ $\text{Ba(NO}_3)_2$ separately undergo a series of reactions using pure reagents.



M, N and P are magnesium compounds.
Q, R and S are barium compounds.

How many of M, N, P, Q, R and S are white precipitates?

Concentrated sulfuric acid is added to separate solid samples of sodium chloride, sodium bromide and sodium iodide.
With which samples does sulfuric acid act as an oxidising agent?

The reaction of bromine with warm NaOH(aq) produces products with the same oxidation numbers, in the same ratios, as the reaction of chlorine with hot NaOH(aq).
In one reaction between bromine and warm NaOH(aq), 30.2 g of a product containing sodium, bromine and oxygen is produced.
Which mass of NaOH has reacted?

At 550°C nitrogen dioxide reacts with unburnt hydrocarbon fragments such as CH₃ in the catalytic converter of a motor vehicle.

$$4\text{CH}_3 + 7\text{NO}_2 \rightarrow 3 \frac{1}{2}\text{N}_2 + 4\text{CO}_2 + 6\text{H}_2\text{O}$$

Which row gives the energy change for this reaction and a possible reason for it?
[Table_1]

Which statement is correct?

The diagrams show two different compounds.
What is
• the total number of structural isomers, including compound 2, that could be formed by adding a second methyl group to the ring of compound 1,
• the number of $\pi$ electrons in each compound?

[Table_1]

Which compound has the molecular formula $C_6H_{10}O$?

What is the structural formula of the major product when hydrogen bromide reacts with 2-methylbut-2-ene?

Which reaction is most likely to involve the formation of a positively charged intermediate?

The infra-red spectrum of a substance with empirical formula $C_2H_4O$ is shown.
Which bonds are responsible for peak X and peak Y?

The structure of coniine is shown.

Coniine can be synthesised by reacting ammonia with a dibromo compound, X.
$$\text{NH}_3 + \text{C}_8\text{H}_{16}\text{Br}_2 \rightarrow \text{coniine} + 2\text{HBr}$$
What is the name of compound X?

Structural isomerism and stereoisomerism should be considered when answering this question.
3-methylhexan-3-ol reacts with hot, concentrated sulfuric acid to form several isomeric compounds with the molecular formula $C_7H_{14}$.
How many isomeric compounds could be formed in this reaction?

An organic compound T undergoes the following reactions.
• T is oxidised by hot, acidified potassium manganate(VII).
• T reacts with sodium to give hydrogen.

What could be compound T?

Compound X is treated with two reagents successively, forming compound Z.
X \[\rightarrow\] Y \[\rightarrow\] Z
What could be Z?

Which reagent may be used to distinguish between propanone and ethanol?

Which compound is chiral?

An atom of calcium-48 can form a 2+ ion.
Which statements about this ion are correct?
1 It has 20 protons.
2 It has 28 neutrons.
3 It has 22 electrons.

Four elements, W, X, Y and Z, have electronic configurations as shown.

[Table_1]

Which formulae represent compounds that have boiling points below room temperature?

Which statements about enthalpy changes are correct?
1. The enthalpy change of atomisation is always positive.
2. The enthalpy change when a C=C bond is broken is positive.
3. The enthalpy change of neutralisation of a weak acid is always negative.

Vanadium and pepsin can both act as catalysts. Vanadium is a metal. Pepsin is an enzyme.
Which statements are correct for both vanadium and pepsin?

Which oxides, when placed in cold water for one day, will react with the water?
1. MgO
2. Al\(_2\)O\(_3\)
3. SiO\(_2\)

A mixture of magnesium carbonate and magnesium nitrate is heated strongly in a hard-glass test-tube.
Which gases are formed?

Which statements about poly(alkene)s are correct?
1 Poly(alkene)s do not react with $\text{Br}_2(\text{aq})$ in the dark.
2 Disposal of poly(alkene)s by combustion can produce harmful products.
3 Poly(alkene)s do not readily biodegrade.

Compound Y reacts with alkaline aqueous iodine to form a yellow precipitate and changes the colour of warm, acidified potassium dichromate(VI) solution. What could be compound Y?

Carboxylic acids can be made by several different reactions.
Which statements are correct?
1. The acid hydrolysis of CH₃CH₂CN will make ethanoic acid.
2. The oxidation of CH₃CH₂CH₂OH will make butanoic acid.
3. The oxidation of CH₃CH₂CHO will make propanoic acid.

Carboxylic acids react with alcohols to produce esters.
Carboxylic acid X forms one ester only with molecular formula $C_5H_{10}O_2$.
What could X be?