AS & A Level Chemistry - 9701 Paper 1 2021 Winter Zone 1

The mass spectrum of a sample of neon is shown. The relative abundance of each peak is written in brackets above it.

What is the relative atomic mass, $A_r$, of this sample of neon?

2.0 g of ammonium nitrate, $\text{NH}_4\text{NO}_3$, decomposes to give 0.90 g of water and a single gas.
What is the identity of the gas?

Which of these elements has the highest fifth ionisation energy?

The ion $X^{2+}$ has the same electronic configuration as the atom Kr.
What is the electronic configuration of an atom of X?

Which type of interaction exists between water molecules and metal cations in aqueous solution?

Which substance shows the greatest deviation from the properties of an ideal gas under room conditions?

In order to determine the enthalpy of neutralisation of a strong acid and a strong alkali, 25.0 cm³ of 2.00 mol dm^-3 sodium hydroxide is added to 25.0 cm³ of 2.00 mol dm^-3 hydrochloric acid. The increase in temperature is 12 °C.

In a second experiment, the same method is used, but 50.0 cm³ of 2.00 mol dm^-3 sodium hydroxide is added to 50.0 cm³ of 2.00 mol dm^-3 hydrochloric acid.

What is the increase in temperature in the second experiment?

Which equation represents the enthalpy change of atomisation of iodine?

Zinc atoms can be oxidised to $\text{Zn}^{2+}$ ions by dichromate(VI) ions in acid solution. Chromium is reduced to $\text{Cr}^{3+}$ in this reaction. Which equation is correct?

The equation shows that H$_2$(g) and I$_2$(g) react to form an equilibrium mixture.
$$ \text{H}_2(g) + \text{I}_2(g) \rightleftharpoons 2\text{HI}(g) \quad \Delta H^\circ = -9.6 \text{kJ mol}^{-1} $$
A mixture containing equal amounts of H$_2$(g) and I$_2$(g) is made at temperature $T_1$ and the composition of the mixture is monitored. A graph of the results is shown.

The experiment is repeated at a lower temperature, $T_2$.
Which new graph would be obtained?

The diagram shows the Boltzmann distribution of energies for a reactant gas. For a particular reaction, the activation energy is X.

Which change to the diagram occurs if an effective catalyst is added at the same temperature?

Which element requires the least number of moles of oxygen for the complete combustion of 1 mol of its atoms?

An element, Y, reacts according to the following sequence:
Y \xrightarrow{ \text{burns in } O_2 } \text{white solid} \xrightarrow{ \text{HCl(aq)} } \text{solution} \xrightarrow{ \text{NaOH(aq)} } \text{white precipitate} \xrightarrow{ \text{an excess of NaOH(aq)} } \text{solution}
What could be element Y?

In which list are all three compounds soluble in water?

Anhydrous magnesium nitrate, $\text{Mg(NO}_3\text{)}_2$, decomposes when heated, giving a white solid and a mixture of two gases, X and Y.
Y is oxygen.
What is the ratio $\frac{\text{mass of X released}}{\text{mass of Y released}}$?

In a series of nine experiments, to test the reactivity of the halogens, an aqueous solution of each halogen is added to an equal volume of an aqueous solution containing halide ions, as shown in the table.

[Table_1]

The nine resulting mixtures are then shaken separately with an equal volume of hexane. The nine tubes are left to stand so that the aqueous and organic solvents separate into layers.

How many test-tubes contain a purple upper hexane layer?

Z is a compound of sodium, chlorine and oxygen. It contains 45.1% by mass of oxygen. Z is prepared by reacting sodium hydroxide with chlorine. Which row shows the conditions used for the reaction and the oxidation state of chlorine in Z? [Table_1: | | reaction conditions | oxidation state of Cl in Z | |---|--------------------------------|---------------------------| | A | cold dilute NaOH | +1 | | B | cold dilute NaOH | +5 | | C | hot concentrated NaOH | +1 | | D | hot concentrated NaOH | +5 | ]

Which row is correct?
[Table_1]

The table describes two possible environmental consequences of adding too much ammonium nitrate fertiliser to the soil.
Which row is correct?
[Table_1]

Hex-2-ene can be made by the reaction shown. Which statement about this reaction is correct?

Structural isomerism only should be considered when answering this question.
Molecule X contains three C=C double bonds. One mole of X is reacted with three moles of HBr. The carbon skeleton is unchanged.
How many different products are formed?

Structural isomerism and stereoisomerism should be considered when answering this question. A colourless liquid, $C_5H_{11}Cl$, exists as a mixture of two optical isomers.
When heated with sodium hydroxide in ethanol, a mixture of only two alkenes is formed.
What could the colourless liquid be?

When 2-bromo-2-methylpropane reacts with aqueous sodium hydroxide, an alcohol is formed.
Which diagram describes the first step in the reaction mechanism?

When an organic compound, Q, is treated with phosphorus pentachloride, fumes of hydrogen chloride are evolved. When Q is warmed with acidified aqueous potassium dichromate(VI), the solution turns green. What is Q?

Alcohol Y gives a yellow precipitate with alkaline aqueous iodine. It can be oxidised to give a mixture of products including substance Z. Substance Z gives a red-brown precipitate with Fehling’s solution.
Which alcohol could be Y?

CH$_3$CH$_2$COCH$_2$CH$_3$ reacts with hydrogen cyanide to form an organic product called a cyanohydrin.
Which statement is correct?

Reduction of compound R with LiAlH₄ gives the compound 4-methylpentane-2,3-diol. What could be the identity of compound R?
[Image_1: Chemical structures of options]

Citric acid is found in lemon juice.
citric acid
$\text{HO}_2\text{CCH}_2\text{C(OH)(CO}_2\text{H)CH}_2\text{CO}_2\text{H}$
Which volume of 0.40 mol dm$^{-3}$ sodium hydroxide solution is required to neutralise a solution containing 0.0050 mol of citric acid?

The structural formula of an ester is $(CH_3)_2CHOCO(CH_2)_2CH_3$.
This ester is boiled with aqueous hydrochloric acid.
Which two products are formed?

The infra-red spectra of three organic compounds are shown.

What could the three compounds be?

Which changes can be used to measure the rates of chemical reactions?
1. the decrease in concentration of a reactant per unit time
2. the rate of appearance of a product
3. the increase in total volume of gas per unit time at constant pressure

Iron reacts with steam to produce hydrogen and an oxide of iron.
$$3 ext{Fe(s)} + 4 ext{H}_2 ext{O(g)} ightleftharpoons ext{Fe}_3 ext{O}_4 ext{(s)} + 4 ext{H}_2 ext{(g)}$$
A system containing all four substances is at equilibrium.
Which changes will decrease the mass of Fe present at equilibrium?
1. addition of steam at constant pressure
2. increase in overall pressure
3. addition of an effective catalyst

Ethyleneglycol, HOCH$_2$CH$_2$OH, is used as a de-icer. It allows ice to melt at temperatures below 0°C.
Which statements are correct?
1. Ethylene glycol disrupts the extensive network of hydrogen bonds in ice.
2. Ethylene glycol molecules form hydrogen bonds with other ethylene glycol molecules.
3. Ethylene glycol molecules will dissolve in the water formed from the ice.

Which molecules contain at least one unpaired electron?

1. NO
2. NO$_2$
3. NH$_3$
[Choose A, B, C, or D based on the criteria given in the instructions at the top]

Which elements form a chloride in which both covalent bonding and coordinate (dative covalent) bonding are present?

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

A diketo acid is a compound with two ketone groups and one carboxylic acid group.

[Image_1: Structure of limonene and terpinolene]

Which statements about the reactions of limonene and terpinolene are correct?
1. When reacted with an excess of hydrogen and a nickel catalyst, limonene and terpinolene produce the same compound.
2. An excess of hot concentrated acidified KMnO$_4$ reacts with limonene and with terpinolene to form different diketo acids.
3. The reactions of limonene and terpinolene with an excess of Br$_2$ produce positional isomers with the same number of chiral carbon atoms.

One molecule of dodecane, $C_{12}H_{26}$, is cracked, producing three product molecules, X, Y and Z.
X is a straight chain alkane. Y and Z are straight chain alkenes with different $M_r$ values.
Which statements about X, Y and Z are correct?
1. If Y and Z are but-1-ene and ethene respectively, X will be hexane.
2. If X is butane, then Y and Z could both show cis-trans isomerism.
3. X could be octane.

Which statements about chlorofluoroalkanes are correct?
1. Both the C–Cl and C–F bonds are readily dissociated by ultra-violet light.
2. They have caused ozone depletion.
3. They are relatively chemically inert.

Which reactions of propan-1-ol have water as one of the products?
1. passing propan-1-ol vapour over hot $Al_2O_3$
2. mixing propan-1-ol with warm ethanoic acid and a few drops of concentrated sulfuric acid
3. warming propan-1-ol with HBr