AS & A Level Chemistry - 9701 Paper 1 2022 Summer Zone 3

Which atom has exactly three unpaired electrons in the ground state?

Which element has the \textit{second} smallest atomic radius in its group and the \textit{second} highest electrical conductivity in its period?

Analysis of the hormone thyroxine gives the results shown.
Heating 0.500 g of thyroxine with aqueous silver nitrate produces 0.604 g of silver iodide. All of the iodine in the thyroxine sample is converted to silver iodide.
Complete combustion of 0.500 g of thyroxine produces 232 cm³ of carbon dioxide and 7.72 cm³ of nitrogen, measured under room conditions.
Which molecular formula of thyroxine agrees with these values?

How many moles of oxygen, $O_2$, are needed to burn 1 mol of ethane if the products of the reaction are water and carbon only?

Which compound has the smallest difference in electronegativity between its two elements?

VSEPR theory should be used to answer this question.
Hydrazine has the following structure.

What is the predicted bond angle X?

This question is about buckminsterfullerene, graphite, iodine and diamond.
How many of these substances have a simple molecular structure?

A student reacts 1 mol of magnesium powder in a sealed 0.030 m³ container of oxygen at a pressure of $2.0 \times 10^5$ Pa and a temperature of 600 K. The magnesium reacts completely to form MgO.
Which percentage of the oxygen will be used up?

Which equation represents an enthalpy change that is the average bond energy of the C–H bond in methane?

Magnesium carbonate decomposes when heated in a Bunsen burner flame.
Values for the standard enthalpies of formation, $\Delta H_f^\circ$, of the species involved are shown.
$\Delta H_f^\circ \text{MgCO}_3 = -1095.8 \text{kJ mol}^{-1}$
$\Delta H_f^\circ \text{MgO} = -601.7 \text{kJ mol}^{-1}$
$\Delta H_f^\circ \text{CO}_2 = -393.5 \text{kJ mol}^{-1}$
What is the standard enthalpy change for the decomposition of magnesium carbonate?

NH$_4$NO$_3$ decomposes into N$_2$O and H$_2$O on heating.
Which statements are correct?
1 The ammonium ion is behaving as a reducing agent.
2 The nitrate(V) ion is behaving as an oxidising agent.
3 It is a redox reaction.
4 It is a disproportionation reaction.

A student adds 3 mol of acidified $K_2Cr_2O_7$ to an excess of $I^-$ ions.
The chromium is all reduced to $Cr^{3+}$ and $I^-$ ions are oxidised to $I_2$.
The $I_2$ released is reduced back to $I^-$ ions by X mol of $S_2O_3^{2-}$ ions.
1 mol of $I_2$ is reduced by 2 mol of $S_2O_3^{2-}$ ions.
What is the value of X?

Which statement about acids and bases is always correct?

The reaction between sulfur dioxide and oxygen is reversible.

$2\text{SO}_{2}(g) + \text{O}_{2}(g) \rightleftharpoons 2\text{SO}_{3}(g) \qquad K_c = 280 \text{ mol}^{-1}\text{dm}^{3} \text{ at } 1000 \text{ K}$

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?

The Boltzmann distribution of the particles in a mixture of gas X and gas Y is shown in diagram 1.

X and Y react and the reaction causes an increase in gas molecules present. The reaction goes to completion.
In experiment 1, the increase in volume is measured every 10 seconds. During the reaction, the temperature and pressure remain constant. The increase in volume is shown in the volume–time graph in diagram 2.

In experiment 2, the experiment is repeated using identical amounts of X and Y. A different temperature is used compared to experiment 1. The same pressure is used. The Boltzmann distribution of the second mixture of X and Y is shown in diagram 3. During the reaction the temperature and pressure remain constant.

Which curve on the volume–time graph would show the increase in volume against time for experiment 2? (The original line for experiment 1 is redrawn as a solid line.)

When the temperature of a particular reaction is increased by 10°C (e.g. from 20°C to 30°C) the rate of the reaction approximately doubles.
What is the most significant reason for this increase?

Which ion has the smallest radius?

Which row is correct?
[Table_1]

Each of the chlorides listed is added to water.

1. aluminium chloride
2. magnesium chloride
3. silicon tetrachloride
4. phosphorus pentachloride

Which chlorides form an aqueous solution that reacts with sodium carbonate to produce carbon dioxide?

NaOH(aq) is added to separate samples of magnesium chloride and barium chloride solutions. H2SO4(aq) is then added slowly to each reaction mixture until in excess.
What is observed at the end of the reaction sequence?
[Table_1: Observation Table with MgCl2(aq) and BaCl2(aq)]

A 4.00 g sample of an anhydrous Group 2 metal nitrate, Z, is heated strongly until there is no further change of mass. A solid residue of mass 1.37 g is formed. Which metal is present in Z?

Chlorine is bubbled through a cylinder containing aqueous sodium iodide and an immiscible layer of hexane.

As the bubbles pass through the cylinder, what is observed in the lower and upper layers?

Chlorine and bromine have different volatilities.
Which row identifies the more volatile of the two elements, and gives the correct explanation? [Table_1]

Ammonium chloride dissolves readily in water.
Which statement about the colourless solution formed is correct?

At 550°C nitrogen dioxide reacts with unburnt hydrocarbon fragments, such as CH3, in the catalytic converter of a motor vehicle.
$$4CH_3 + 7NO_2 \rightarrow 3\frac{1}{2}N_2 + 4CO_2 + 6H_2O$$
Which row gives the energy change for this reaction and a possible reason for it?

Compound X contains an alcohol group and a carbonyl group.
[Image_1: compound X structure]
Which row is correct?
[Table_1: type of alcohol group and type of carbonyl group]
A. primary, aldehyde
B. primary, ketone
C. tertiary, aldehyde
D. tertiary, ketone

The diagram shows the skeletal formula of phenazine.

What is the empirical formula of phenazine?

The diagram shows the structural formula of mevalonic acid.

Which reagent and conditions will react with mevalonic acid to produce an organic compound without a chiral carbon atom?

Structural isomerism and stereoisomerism should be considered when answering this question.
Y is a gaseous hydrocarbon which decolourises aqueous bromine.
10.0 g of Y occupies a volume of 3.43 dm^3 under room conditions.
How many isomeric structures are possible for Y?

Limonene is found in lemon and orange oils.
What is the major product when limonene reacts with an excess of dry hydrogen chloride?

Which statement concerning the hydrolysis of 1-bromopropane with water is correct?

Compound J, $\text{C}_{15}\text{H}_{23}\text{Br}_2\text{Cl}$, is reacted with an excess of a hot concentrated solution of sodium hydroxide in ethanol. One of the products is X.

What could be the skeletal formula of X?

Structural isomerism only should be considered when answering this question.
Several compounds with molecular formula $C_4H_8O_2$ have one carbonyl group and one OH group.
How many of these compounds produce yellow crystals with alkaline $I_2(aq)$ at room temperature?

Pentaerythritol is used as an intermediate in the manufacture of paint.

Which statement is correct?

Which reaction has a nucleophilic addition mechanism and gives a good yield of product under the stated conditions?

A carbonyl compound has the structural formula CH$_3$COCHO. Which row is correct for the observations made when this compound is treated with the given reagents?
[Table_1]

An ester is shown.
Which two compounds react to form this ester?

Which compound can be used to make propanoic acid by treatment with a single reagent?

A sample of sulfur consists mostly of $^{32}\text{S}$. It also contains 4.2% $^{34}\text{S}$ and 2.8% $^{36}\text{S}$. No other isotopes of sulfur are present.
What is the relative atomic mass, $A_r$, of this sample of sulfur?

One molecule of an addition polymer containing 2000 repeat units has an $M_r$ of 112000.
The polymer molecule contains chiral centres.
What is a possible monomer for this polymer?