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Questions 1

Topic -1.1 Particles in the atom and atomic radius

Sodium azide, NaN₃, is an explosive used to inflate airbags in cars when they crash. It consists of positive sodium ions and negative azide ions. What are the numbers of electrons in the sodium ion and the azide ion?

▶️Answer/Explanation

Ans: B

Questions 2

Topic -1.4 Ionisation energy

The graph shows the variation of the first ionisation energy with proton number for some elements. The letters used are not the actual symbols for the elements.

Which statement about the elements is correct?
A P and X are in the same period in the Periodic Table.
B The general increase from Q to X is due to increasing atomic radius.
C The small decrease from R to S is due to decreased shielding.
D The small decrease from U to V is due to repulsion between paired electrons.

▶️Answer/Explanation

Ans: D

Questions 3

Topic -13.1 Formulas, functional groups and the naming of organic compounds

Aluminium carbide, Al₄C₃, reacts readily with aqueous sodium hydroxide. The two products of the reaction are NaAlO₂ and a hydrocarbon. Water molecules are also involved as reactants. What is the formula of the hydrocarbon?
A \(CH_4\)

B \(C_2H_6\)

C \(C_3H_8\)

D \(C_6H_{12}\)

▶️Answer/Explanation

Ans: A

Questions 4

Topic -1.1 Particles in the atom and atomic radius 

A sample of 35.6 g of hydrated sodium carbonate contains 25.84% sodium ions by mass. When this sample is heated, anhydrous sodium carbonate and water are formed. Which mass of water is given off?
A 7.2 g

B 10.6 g

C 14.4 g

D 21.2 g

▶️Answer/Explanation

Ans: C

Questions 5

Topic -2.1 Relative masses of atoms and molecules

Solid aluminium chloride sublimes at 178 °C. Which structure best represents the species in the vapour at this temperature?

▶️Answer/Explanation

Ans: A

Questions 6

Topic -4.2 Bonding and structure 

Which row is correct?

▶️Answer/Explanation

Ans: A

Questions 7

Topic -4.1 The gaseous state: ideal and real gases and 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 is the identity of the gas?
A argon
B helium
C krypton
D neon

▶️Answer/Explanation

Ans: A

Questions 8

Topic -12.1 Nitrogen and sulfur

Nitrogen, N₂, and carbon monoxide, CO, both have \(M_r = 28\). The boiling point of N₂ is 77 K. The boiling point of CO is 82 K. What could be responsible for this difference in boiling points?
A CO molecules have a permanent dipole; the N₂ molecules are not polar.
B N₂ has and bonding; CO has bonding only.
C N₂ has a strong N≡N bond; CO has a C=O bond.
D The CO molecule has more electrons than the N₂ molecule

▶️Answer/Explanation

Ans: A

Questions 9

Topic -5.1 Enthalpy change, ΔH

Which statement about enthalpy changes is correct?
A Enthalpy changes of reaction are always negative.
B Enthalpy changes of combustion are always positive.
C Enthalpy changes of formation are always positive.
D Enthalpy changes of neutralisation are always negative.

▶️Answer/Explanation

Ans: D

Questions 10

Topic -5.1 Enthalpy change, ΔH

What is the definition of standard enthalpy change of neutralisation, \(\Delta H^0_{neut}\)?
A \(\Delta H^0_{r}\) when one mole of an aqueous acid is neutralised by an aqueous alkali
B \(\Delta H^0_{r}\) when one mole of an aqueous alkali is neutralised by an aqueous acid
C \(\Delta H^0_{r}\) when one mole of an aqueous acid is neutralised by one mole of an aqueous alkali
D \(\Delta H^0_{r}\) when an aqueous acid and an aqueous alkali react together to produce one mole of water

▶️Answer/Explanation

Ans: D

Questions 11

Topic -24.2 Standard electrode potentials, standard cell potentials and the Nernst equation

HOCl(aq) is the molecule that kills bacteria when chlorine is added to water. The following reaction produces this molecule.
\(Cl_2(g) + H_2O(l) \rightleftharpoons HOCl(aq) + H^+(aq) + Cl^– (aq)\)
Which statement about this reaction is correct?
A Chlorine is both oxidised and reduced.
B Chlorine is oxidised but not reduced.
C Hydrogen is both oxidised and reduced.
D Hydrogen is oxidised but not reduced.

▶️Answer/Explanation

Ans: A

Questions 12

Topic -7.1 Chemical equilibria: reversible reactions, dynamic equilibrium

Nitrogen dioxide, NO₂, exists in equilibrium with dinitrogen tetroxide, N₂O₄.
\(2NO_2(g) \rightleftharpoons N_2O_4(g) \) \(H = –57 kJ mol^{–1}\)
Which conditions give the greatest percentage of \(N_2O_4(g)\) at equilibrium?

▶️Answer/Explanation

Ans: B

Questions 13

Topic -7.1 Chemical equilibria: reversible reactions, dynamic equilibrium

When an equimolar mixture of \(H_2\) and \(I_2\) react, the mole fraction of HI in the final mixture is x. What is the equilibrium constant, \(K_p\), for the reaction?

A \(\frac{x^2}{(1-x)^2}\)

B\(\frac{x^2}{(1-2x)^2}\)

C\(\frac{4x^2}{(1-x)^2}\)

D\(\frac{4x^2}{(1-2x)^2}\)

▶️Answer/Explanation

Ans: C

Questions 14

Topic -8.1 Rate of reaction

In reaction 1, a student measures the initial rate of production of CO₂(g) when CuCO₃(s) is added to 50 cm³ of 0.1 mol dm⁻³ HNO₃(aq).
In reaction 2, the student repeats the experiment using 50 cm³ of 0.5 mol dm⁻³ HNO₃ (aq) and the same mass of CuCO₃ (s).
In reaction 1 and reaction 2, the acid is in excess and samples of the same CuCO₃ powder are used. Which row is correct?

▶️Answer/Explanation

Ans: D

Questions 15

Topic -8.2 Effect of temperature on reaction rates and the concept of activation energy

The forward reaction of a reversible reaction is exothermic and has an activation energy of +30 kJ mol⁻¹. The reverse reaction proceeds by a mechanism that is the exact reverse of the mechanism of the forward reaction. Which statement about the activation energy of the reverse reaction is correct?
A The activation energy for the reverse reaction is equal to –30 kJ mol⁻¹
B The activation energy for the reverse reaction is greater than 0 kJmol⁻¹ but less than +30 kJ mol⁻¹
C The activation energy for the reverse reaction is equal to +30 kJ mol⁻¹. 
D The activation energy for the reverse reaction is greater than +30 kJ mol⁻¹ 

▶️Answer/Explanation

Ans: D

Questions 16

Topic -9 The Periodic Table: chemical periodicity

X, Y and Z are elements all found within Groups 13, 14 and 15 of the Periodic Table. X is in the same group in the Periodic Table as Y. Y and Z are in Period 3. The first ionisation energy of X is greater than the first ionisation energy of Y. The melting point of Z is less than the melting point of Y. Y and Z both form chlorides which are white solids. These white solids react with water to produce solutions with a pH of less than 4. Which row of the table shows the possible identities of X and Y?

▶️Answer/Explanation

Ans: D

Questions 17

Topic -9.2 Periodicity of chemical properties of the elements in Period 3

Which row about silicon, Si, and magnesium, Mg, and their ions is correct?

▶️Answer/Explanation

Ans: D

Questions 18

Topic -11.1 Physical properties of the Group 17 elements

Bromocresol green is an acid-base indicator. Below a pH of 3.8 it is yellow. Above a pH of 5.4 it is blue. Between these values it is green. Bromocresol green is added to the aqueous solution formed when the chloride of element T is added to water. The colour becomes yellow. When an excess of the solid oxide of element U is slowly added to this yellow solution, the indicator turns green then blue. Which row could identify element T and element U?

▶️Answer/Explanation

Ans: A

Questions 19

Topic -9 The Periodic Table: chemical periodicity

Which row correctly describes the separate reactions of calcium and strontium with water?

▶️Answer/Explanation

Ans: D

Questions 20

Topic -10.1 Similarities and trends in the properties of the Group 2 metals, magnesium to barium, and their compounds

L and M are both compounds of Group 2 elements. L and M are both soluble in water. When solutions of L and M are mixed, a white precipitate is formed. What could be L and M?
A barium chloride and magnesium sulfate
B barium sulfate and magnesium chloride
C barium nitrate and magnesium chloride
D barium carbonate and magnesium nitrate

▶️Answer/Explanation

Ans: A

Questions 21

Topic -10.1 Similarities and trends in the properties of the Group 2 metals, magnesium to barium, and their compounds

A 5.00 g sample of an anhydrous Group 2 metal nitrate loses 3.29 g in mass when heated strongly. Which metal is present?
A magnesium
B calcium
C strontium
D barium

▶️Answer/Explanation

Ans: B

Questions 22

Topic -11.2 The chemical properties of the halogen elements and the hydrogen halides

In this question, Q represents an atom of chlorine, bromine or iodine. Which explanation for the variation in volatility down Group 17 is correct?
A Instantaneous dipole–induced dipole forces between molecules become stronger.
B Permanent dipole–permanent dipole forces between molecules become stronger.
C The bond energy of the \(Q_2\) molecules decreases.
D The first ionisation energy \(Q(g) → Q^+(g) + e^–\) decreases.

▶️Answer/Explanation

Ans: A

Questions 23

Topic -11.2 The chemical properties of the halogen elements and the hydrogen halides

Which statement about the halogens or halide ions is correct?
A Bromide ions react to form a white precipitate when added to silver nitrate solution.
B Bromine does not oxidise chloride ions when added to sodium chloride solution.
C Fluorine atoms form cations by accepting electrons when they react.
D Chloride ions are stronger reducing agents than iodide ions.

▶️Answer/Explanation

Ans: B

Questions 24

Topic -17.1 Aldehydes and ketones 

If ammonium cyanate is heated in the absence of air, the only product of the reaction is urea, CO(NH₂)₂. No other products are formed in the reaction. What is the formula of the cyanate ion present in ammonium cyanate?

A\(CON_2^-\)

B\(CON_2^{2-}\)

C\(OCN^-\)

D\(OCN^{2-}\)

▶️Answer/Explanation

Ans: C

Questions 25

Topic -13.1 Formulas, functional groups and the naming of organic compounds

Hexamine is a crystalline solid used as a fuel in portable stoves. The diagram shows its skeletal structure.

A\(CH_2N\)

B\(C_3H_6N_2\)

C\(C_4H_8N_4\)

D\(C_6H_{12}N_4\)

▶️Answer/Explanation

Ans: B

Questions 26

Topic -13.1 Formulas, functional groups and the naming of organic compounds

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 1

B 2

C 3

D 4

▶️Answer/Explanation

Ans: B

Questions 27

Topic -3.4 Covalent bonding and coordinate (dative covalent) bonding

How many \(\sigma\) and \(\pi\) bonds are in the molecule HCCCH₂CH₂CHC(CH₃)?
A 17\(\sigma\) 3\(\pi\)

B 17\(\sigma\) 5\(\pi\)

C 18 \(\sigma\)4\(\pi\)

D 19\(\sigma\) 3\(\pi\)

▶️Answer/Explanation

Ans: D

Questions 28

Topic -14 Hydrocarbons

The hydrocarbon \(C_{17}H_{36}\) can be cracked. Which compound is the least likely to be produced in this reaction?
A \(C_3H_8\)

B \(C_4H_8\)

C \(C_8H_{16}\)

D \(C_{16}H_{34}\)

▶️Answer/Explanation

Ans: D

Questions 29

Topic -14 Hydrocarbons

Which compound has an \(M_r\) of 84 and will react with HBr to give a product with an \(M_r\) of 164.9?

▶️Answer/Explanation

Ans: D

Questions 30

Topic -13.1 Formulas, functional groups and the naming of organic compounds

β-carotene is responsible for the orange colour of carrots.

β-carotene is oxidised by hot, concentrated, acidified \(KMnO_4\). When an individual molecule of β-carotene is oxidised in this way, many product molecules are formed. How many of these product molecules contain a ketone functional group?
A 4

B 6

C 9

D 11

▶️Answer/Explanation

Ans: B

Questions 31

Topic -13.2 Characteristic organic reactions

1,1-dichloropropane reacts with aqueous sodium hydroxide in a series of steps to give propanal.

Which term describes the first step of this reaction?
A addition
B elimination
C oxidation
D substitution

▶️Answer/Explanation

Ans: D

Questions 32

Topic -13.2 Characteristic organic reactions

Propanoic acid can be made from bromoethane using a two-stage synthesis. Which pair of reagents is most suitable?

▶️Answer/Explanation

Ans: D

Questions 33

Topic -16.1 Alcohols

Alcohol X gives a yellow precipitate with alkaline \(I_2\)(aq). What is the structure of X?

▶️Answer/Explanation

Ans: D

Questions 34

Topic -16.1 Alcohols

When ethanol reacts with sodium metal, ethoxide ions, CH₃CH₂O⁻, are produced. When water reacts with sodium metal, OH⁻ ions are produced. Which statement about these reactions and the ethoxide ion is correct?
A At the same temperature, the rate of reaction between sodium and ethanol is greater than that between sodium and water.
B CH₃CH₂O⁻ is a stronger base than OH⁻ due to the electron-donating effect of the ethyl group.
C The negative charge on the oxygen in an ethoxide ion is delocalised.
D It is easier to deprotonate ethanol as it is more acidic than water.

▶️Answer/Explanation

Ans: B

Questions 35

Topic -16.1 Alcohols

Menthol is a naturally occurring alcohol.

When menthol is heated with concentrated sulfuric acid it reacts. The products formed include compound T. What is the structure of compound T?

▶️Answer/Explanation

Ans: D

Questions 36

Topic -16.1 Alcohols

Which compound will produce a yellow-orange precipitate when added to 2,4-dinitrophenylhydrazine?

▶️Answer/Explanation

Ans: D

Questions 37

Topic -17.1 Aldehydes and ketones

Ethanal, CH₃CHO, undergoes an addition reaction with HCN in the presence of CN⁻ ions. Which row identifies the type of reaction and the name of the product formed?

▶️Answer/Explanation

Ans: C

Questions 38

Topic -17.1 Aldehydes and ketones

The structure of compound X is shown.

What is produced when X is heated with NaOH(aq)?

▶️Answer/Explanation

Ans: C

Questions 39

Topic -22.1 Infrared spectroscopy

The infrared spectrum of compound L is shown.

 

What is the structure of L?
A \(HOCH_2COCH_2OH\)
B \(HOCH_2CH(OH)CHO\)
C \(HOCH_2CH(OH)CH_2OH\)
D \(HOCH_2CH_2COOH\)

▶️Answer/Explanation

Ans: C

Questions 40

Topic – 22.2 Mass spectrometry

In the mass spectrum of compound J, the ratio of the height of the M +1 ion peak to the height of the M + ion peak is 4 : 91. Compound J forms a carboxylic acid when heated with acidified K₂Cr₂O₇. What is compound J?
A butanal
B butanone
C propan-1-ol
D propanenitrile

▶️Answer/Explanation

Ans: A

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