Questions 1
Topic -22.2 Mass spectrometry
When chlorine gas is analysed in a mass spectrometer \(^{35}Cl^+\) ions are detected. Which row is correct?
▶️Answer/Explanation
Ans: C
Questions 2
Topic -1.3 Electrons, energy levels and atomic orbitals
Which species is a free radical?
A He
B \(Be^-\)
C \(O^{2-}\)
D Zn
▶️Answer/Explanation
Ans: B
Questions 3
Topic -1.4 Ionisation energy
Which statement is correct?
A The first ionisation energy of chlorine is more than the first ionisation energy of argon.
B The second ionisation energy of calcium is more than the second ionisation energy of magnesium.
C The second ionisation energy of sulfur is equal to the first ionisation energy of phosphorus.
D The eighth ionisation energy of chlorine is more than the first ionisation energy of neon.
▶️Answer/Explanation
Ans: D
Questions 4
Topic -2.2 The mole and the Avogadro constant
If 1 mole of hexane combusts in an excess of oxygen, how many moles of products are formed?
A 11
B 12
C 13
D 14
▶️Answer/Explanation
Ans: C
Questions 5
Topic -8.3 Homogeneous and heterogeneous catalysts
Separate samples, each of mass 1.0 g, of the compounds listed are treated with an excess of dilute acid. Which compound releases the largest amount of CO₂?
A 1.0 g CaCO₃
B 1.0 g Li₂CO₃
C 1.0 g MgCO₃
D 1.0 g Na₂CO₃
▶️Answer/Explanation
Ans: B
Questions 6
Topic -13.3 Shapes of organic molecules; σ and π bonds
Which statement about the Cl –N=O molecule is correct?
A Each molecule contains one σ and two π bonds.
B It is a non-polar molecule.
C It is a linear molecule.
D The nitrogen atom is \(sp^2\) hybridised .
▶️Answer/Explanation
Ans: D
Questions 7
Topic -13.3 Shapes of organic molecules; σ and π bonds
Which row is correct?
▶️Answer/Explanation
Ans: B
Questions 8
Topic -4.1 The gaseous state: ideal and real gases and pV = nRT
The volume of a vessel is \(1.20 \times 10^{–3} m^3\). It contains pure argon at a pressure of \(1.00 \times 10^5 Pa\) and at a temperature of 25.0°C. Under these conditions it can be assumed that argon behaves as an ideal gas. Which mass of argon does it contain?
A 0.0485 g
B 1.93 g
C 10.4 g
D 23.0 g
▶️Answer/Explanation
Ans: B
Questions 9
Topic -5.1 Enthalpy change, ΔH
A student mixed 25.0 \(cm^3\) of 4.00 \(mol dm^{–3}\) hydrochloric acid with an equal volume of 4.00 mol dm⁻³ sodium hydroxide. The initial temperature of both solutions was 15.0°C. The maximum temperature recorded was 30.0°C. The heat capacity of the final solution can be assumed to be \(4.18 J K^{–1} g^{–1}\) and the density of this solution can be assumed to be \(1.00 g cm^{–3}\). Using these results, what is the enthalpy change of neutralisation of hydrochloric acid?
A –62.7\( kJ mol^{–1}\)
B –31.4 \( kJ mol^{–1}\)
C –15.7 \( kJ mol^{–1}\)
D –3.14 \( kJ mol^{–1}\)
▶️Answer/Explanation
Ans: B
Questions 10
Topic -5.1 Enthalpy change, ΔH
Nitrogen monoxide is rapidly oxidised to nitrogen dioxide.
\(2NO(g) + O_2(g) \to 2NO_2(g)\)
Nitrogen dioxide can then dimerise to form dinitrogen tetroxide.
What is the value of the standard enthalpy change for the reaction shown?
\(2NO(g) + O_2(g) \to N_2O_4(g)\)
A +56 \(kJ mol^{ –1}\)
B –1 \(kJ mol^{ –1}\)
C –115 \(kJ mol^{ –1}\)
D –172 \(kJ mol^{ –1}\)
▶️Answer/Explanation
Ans: D
Questions 11
Topic -2.3 Formulas
\(LiAlH_4\) contains \(AlH_4^–\) ions in which aluminium has an oxidation state of +3. \(LiAlH_4\) reacts with water, as shown.
\(LiAlH_4 + 4H_2O \to 4H_2 + LiOH + Al(OH)_3\)
In this reaction, each of the four water molecules produces one hydroxide ion. It does this by losing one \(H^+\) ion, which reacts with the \(LiAlH_4\). Which changes in oxidation number occur in this reaction?
A Al increases by 1 and H decreases by 1.
B H decreases by 2 and also increases by 1.
C H increases by 1 and also decreases by 1.
D O decreases by 1 and H increases by 1.
▶️Answer/Explanation
Ans: C
Questions 12
Topic -2.3 Formulas
The vanadium salt, VOSO₄, is soluble in water and reacts readily with powdered manganese in dilute sulfuric acid. The equation for the reaction is shown.
Mn(s) + 2VOSO₄(aq) + 2H₂SO₄(aq) → V₂(SO₄)₃(aq) + MnSO₄(aq) + 2H₂O(l)
Which statement about this reaction is correct?
A Hydrogen is oxidised in the reaction.
B Manganese is the reducing agent in this reaction.
C Sulfuric acid is the oxidising agent in this reaction.
D The oxidation state of the vanadium changes from +5 to +3.
▶️Answer/Explanation
Ans: B
Questions 13
Topic -7.1 Chemical equilibria: reversible reactions, dynamic equilibrium
In which equilibrium will an increase in pressure at constant temperature increase the yield of the products on the right-hand side of the equation?
▶️Answer/Explanation
Ans: B
Questions 14
Topic -7.1 Chemical equilibria: reversible reactions, dynamic equilibrium
Hydrogen iodide is added to an evacuated reaction vessel. The vessel is sealed and warmed. A decomposition reaction occurs. Hydrogen and iodine are formed. Some hydrogen iodide remains. When equilibrium is established, the total pressure is \(1.20 \times 10^5Pa\). The partial pressure of hydrogen is \(4.00 \times 10^3Pa\). Hydrogen iodide, hydrogen and iodine are all gaseous under the conditions used. What is the value of \(K_p\) for the equilibrium at this temperature, assuming the decomposition is the forward reaction?
A \(1.19 \times 10^{ –3}\)
B \(1.28 \times 10^{ –3}\)
C \(1.38 \times 10^{ –3}\)
D \(1.43 \times 10^{ –3}\)
▶️Answer/Explanation
Ans: B
Questions 15
Topic -8.1 Rate of reaction
The equations for two reactions are shown.
reaction X 2NOBr → 2NO + Br₂
reaction Y 2NOCl → 2NO + Cl₂
The two reactions have similar reaction mechanisms. The initial rate of reaction X is greater than that of reaction Y when measured under identical conditions of temperature, pressure and reactant concentration. Which statements explain this difference?
1 The activation energy for reaction X is less than that of reaction Y.
2 The Br−Br bond is weaker than the Cl−Cl bond.
3 A higher frequency of collisions between molecules of NOBr occur than between molecules of NOCl.
A 1 and 2
B 2 and 3
C 1 only
D 3 only
▶️Answer/Explanation
Ans: C
Questions 16
Topic -8.2 Effect of temperature on reaction rates and the concept of activation energy
The diagram shows the Boltzmann distribution of energies in a gas. The gas can take part in a reaction with an activation energy, \(E_a\). The gas is maintained at a constant temperature.
Which statement is correct?
A If a catalyst is added, peak P will be lower and \(E_a\) will move to the left.
B If a catalyst is added, peak P will be lower and \(E_a\) will move to the right.
C If a catalyst is added, peak P will be the same and \(E_a\) will move to the left.
D If a catalyst is added, peak P will be the same and \(E_a\) will move to the right.
▶️Answer/Explanation
Ans: C
Questions 17
Topic -9.1 Periodicity of physical properties of the elements in Period 3
L, M and N are three different elements from Period 3 of the Periodic Table. L is the element whose atoms have three unpaired electrons in its 3p sub-shell. M is the element with the highest electrical conductivity in the period. N is the element with the highest melting point in the period. Which statement about element L is correct?
A L has a higher atomic number than M and a lower atomic number than N.
B L has a lower atomic number than M and a higher atomic number than N.
C L has a lower atomic number than both M and N.
D L has a higher atomic number than both M and N.
▶️Answer/Explanation
Ans: D
Questions 18
Topic -9.1 Periodicity of physical properties of the elements in Period 3
In reactions 1 and 2, X represents an element in Period 3. In each reaction, X is forming a product where X is in its highest oxidation state.
reaction 1 chlorine + element X → \(X_yCl_z\)
reaction 2 oxygen + element X → \(X_pO_q\)
Which ratios show a steady increase from sodium to phosphorus?
A neither z : y nor q : p
B z : y only
C q : p only
D both z : y and q : p
▶️Answer/Explanation
Ans: D
Questions 19
Topic -9.1 Periodicity of physical properties of the elements in Period 3
Sodium, magnesium, aluminium, silicon and phosphorus are all elements in Period 3 of the Periodic Table. Three statements about the oxides and chlorides of these elements are given.
1 The ionically bonded oxides all react with dilute hydrochloric acid.
2 All metal chlorides produce neutral solutions when added to water.
3 The two most electronegative elements both form covalently bonded chlorides.
Which statements are correct?
A 1, 2 and 3
B 1 and 2 only
C 1 and 3 only
D 2 and 3 only
▶️Answer/Explanation
Ans: C
Questions 20
Topic – 11.2 The chemical properties of the halogen elements and the hydrogen halides
The table compares calcium with barium and calcium carbonate with barium carbonate. Which row is correct?
▶️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
Solutions P and Q each contain a different Group 2 ion at the same concentration. One contains Mg²⁺ and the other contains Ba²⁺. Tests are carried out on separate 5 cm³ samples of P and Q.
test 1: add 1 cm³ of 0.1 mol dm⁻³ Na₂SO₄(aq)
test 2: add 1 cm³ of 0.1 mol dm⁻³ NaOH(aq)
What are the results of these tests?
▶️Answer/Explanation
Ans: B
Questions 22
Topic -10.1 Similarities and trends in the properties of the Group 2 metals, magnesium to barium, and their compounds
J dissolves in water to give an aqueous solution K. K gives a dense white precipitate when aqueous silver nitrate is added. When heated with aqueous potassium hydroxide, K gives off a gas that turns moist universal indicator paper blue. What is J?
A ammonium chloride
B ammonium sulfate
C sodium chloride
D sodium hydroxide
▶️Answer/Explanation
Ans: A
Questions 23
Topic -12.1 Nitrogen and sulfur
Ammonium sulfate, (NH₄)₂SO₄, and ammonium nitrate, NH₄NO₃, are used as fertilisers. These salts have different percentages by mass of nitrogen. They have the same effect as each
other on the pH of wet neutral soil. Which row is correct?
▶️Answer/Explanation
Ans: A
Questions 24
Topic -7.1 Chemical equilibria: reversible reactions, dynamic equilibrium
The equation shows a reaction that occurs between carbon monoxide and nitrogen monoxide in a catalytic converter.
\(2CO(g)+2NO(g)\to 2CO_2(g)+N_2(g)\)
Which statement is correct?
A The catalyst used is finely divided iron.
B The reaction prevents greenhouse gas emissions into the atmosphere.
C The reaction reduces the possibility of the formation of photochemical smog.
D The reaction results in increased ozone depletion.
▶️Answer/Explanation
Ans: C
Questions 25
Topic -13.3 Shapes of organic molecules; σ and π bonds
Which compound has the molecular formula C₆H₁₀O?
▶️Answer/Explanation
Ans: A
Questions 26
Topic -13.4 Isomerism: structural isomerism and stereoisomerism
The general formula for a non-cyclic alcohol is CnH₂n₊₁OH. How many different structural isomers are there for n = 3 and n = 4?
▶️Answer/Explanation
Ans: B
Questions 27
Topic -13.4 Isomerism: structural isomerism and stereoisomerism
Compound X, \(C_5H_{10}O_3\), has one chiral carbon atom per molecule. Compound X produces bubbles with Na but not with Na₂CO₃. Which formula could represent compound X?
A (CH₃)₂C(OH)CO₂CH₃
B HOCH₂CH(CH₃)CO₂CH₃
C CH₃CH₂C(CH₃)(OH)CO₂H
D CH₃CH(OH)CH(CH₃)CO₂H
▶️Answer/Explanation
Ans: B
Questions 28
Topic -14.1 Alkanes
Ethane reacts with an excess of chlorine in the presence of ultraviolet light to form a mixture of products. How many of these products contain two carbon atoms and one or more chlorine atoms?
A 6
B 7
C 8
D 9
▶️Answer/Explanation
Ans: D
Questions 29
Topic -14.1 Alkanes
When bromoethane reacts with hot ethanolic sodium hydroxide a colourless gas is formed. This gas decolourises aqueous bromine. What is the colourless gas?
A 1,2-dibromoethane
B ethanol
C ethene
D hydrogen bromide
▶️Answer/Explanation
Ans: C
Questions 30
Topic -14.2 Alkenes (continued)
Alkynes are hydrocarbons that contain one triple C≡C bond. Like alkenes, alkynes take part in addition reactions. A saturated compound can be formed. For example, ethyne, H–C≡C–H, reacts with an excess of hydrogen to form ethane. Propyne, C₃H₄, undergoes an addition reaction with an excess of hydrogen bromide in two stages. Markovnikov’s rule applies to the addition of HBr at each stage. What is the main product obtained when propyne reacts with an excess of hydrogen bromide?
A CH₂BrCH₂CH₂Br
B CH₃CH₂CHBr₂
C CH₃CHBrCH₂Br
D CH₃CBr₂CH₃
▶️Answer/Explanation
Ans: D
Questions 31
Topic -14.2 Alkenes
Bromine reacts with alkenes by an electrophilic addition mechanism in which a cation is formed as an intermediate. Which mixture will produce the most stable intermediate cation?
A 3,3-dimethylpent-1-ene + bromine
B ethene + bromine
C methylpropene + bromine
D propene + bromine
▶️Answer/Explanation
Ans: C
Questions 32
Topic -14.1 Alkanes
Halogenoalkanes react with hot ethanolic potassium cyanide. The reaction mechanism is either \(S_N1\) or \(S_N2\). Which statement is correct?
A All secondary halogenoalkanes react by the \(S_N2\) mechanism only.
B Both the halogenoalkane and the cyanide ion are involved in the initial step of the \(S_N1\) mechanism.
C Chloroethane reacts with cyanide ions by the \(S_N1\) mechanism only.
D The \(S_N2\) mechanism involves a short-lived negatively charged transition state.
▶️Answer/Explanation
Ans: D
Questions 33
Topic -15.1 Halogenoalkanes
X, Y and Z are three isomeric alcohols.
X CH₃CH₂CH₂CH₂CH₂OH
Y CH₃CH₂CH(OH)CH₂CH₃
Z (CH₃)₂C(OH)CH₂CH₃
Separate samples of each alcohol are warmed with a mild oxidising agent and the results noted. One of these alcohols, when dehydrated, will give a pair of cis-trans isomers with molecular formula \(C_5H_{10}\). Which row is correct?
▶️Answer/Explanation
Ans: C
Questions 34
Topic -15.1 Halogenoalkanes
Compound G gives a pale yellow precipitate with alkaline \(I_2(aq)\). What could be compound G?
A pentan-1-ol
B pentan-2-ol
C pentan-3-ol
D 2-methylpentan-2-ol
▶️Answer/Explanation
Ans: B
Questions 35
Topic -15.1 Halogenoalkanes
The mechanism for the reaction between ethanal and hydrogen cyanide starts with the step shown.
What is the correct structure of the intermediate ion formed, and what is the next step in this mechanism?
▶️Answer/Explanation
Ans: D
Questions 36
Topic -17.1 Aldehydes and ketones
Which compound reacts with 2,4-dinitrophenylhydrazine reagent but does not react with Tollens’ reagent?
A CH₃COCO₂H
B CH₃CH(OH)CHO
C CH₃COCHO
D CH₃CH(OH)CH₃
▶️Answer/Explanation
Ans: A
Questions 37
Topic -33.1 Carboxylic acids
Compound X has stereoisomers and forms a precipitate when warmed with Fehling’s reagent. What could be the structure of compound X?
▶️Answer/Explanation
Ans: D
Questions 38
Topic -33.1 Carboxylic acids
Which reaction will form propanoic acid?
A acidic hydrolysis of propyl ethanoate
B alkaline hydrolysis of ethyl propanoate
C acidic hydrolysis of propanenitrile
D acidic hydrolysis of ethanenitrile
▶️Answer/Explanation
Ans: C
Questions 39
Topic -33.1 Carboxylic acids
Lactide is an intermediate in the manufacture of a synthetic fibre.
Which compound, on heating with an acid catalyst, can produce lactide?
A hydroxyethanoic acid
B 2-hydroxybutanoic acid
C 2-hydroxypropanoic acid
D 3-hydroxypropanoic acid
▶️Answer/Explanation
Ans: C
Questions 40
Topic -1.2 Isotopes
The diagram shows the relative abundance of different isotopes of lead in a sample of lead ore. The abundance of 208 is half that of 206. The abundances of 208 and 209 are equal.
What is the relative atomic mass of the lead in the sample?
A 207.00
B 207.25
C 207.50
D 207.67
▶️Answer/Explanation
Ans: D