AS Level Chemistry A H032/01 Breadth in chemistry

Which compound has the highest boiling point? A ethanol B heptane C sodium chloride D water Your answer [1] 2 Pauling electronegativity values for the halogens F to I and some elements in period 2 of the periodic table are shown below. B 2.04 C 2.55 N 3.04 O 3.44 F 3.98 Cl 3.16 Br 2.96 I 2.66 Which bond has the correct polarity? A B C D δ– N—I δ+ δ– C—F δ+ δ– B—Cl δ+ δ– Br—Cl δ+ Your answer [1] 3 © OCR 2021 Turn over 3 Which compound releases hydroxide ions when it dissolves in water? A CH3COOH B HNO3 C H2SO4 D NH3 Your answer [1] 4 Which alkane is 82.8% carbon by mass? A CH4 B C2H6 C C4H10 D C8H18 Your answer [1] 5 Which gas sample has the greatest mass at RTP? A 50cm3 of Ar(g) B 100cm3 of O2(g) C 150cm3 of N2(g) D 200cm3 of Ne(g) Your answer [1] 4 © OCR 2021 6 A student mixes 250.0cm3 of 0.100moldm–3 KOH with 750.0cm3 of 0.100moldm–3Ca(OH)2. What is the OH– concentration, in moldm–3, in the resulting mixture? A 0.0250 B 0.100 C 0.150 D 0.175 Your answer [1] 7 After delivering a solution from a pipette, a droplet remains in the tip of the pipette. How should a student ensure that the pipette delivers the volume of solution stated on the pipette? A Fill the pipette just above the graduation line to compensate for the volume of the droplet that remains in the tip. B Leave the droplet in the tip. C Shake the pipette to force out the droplet left in the tip. D Use a pipette filler to force the droplet out of the tip. Your answer [1] 8 Which sequence has elements in order of increasing first ionisation energy? A Na Mg Al B Mg Al Si C Al Si P D Si P S Your answer [1] 5 © OCR 2021 Turn over 9 Which element has atoms with the largest number of unpaired p-electrons? A aluminium B oxygen C chlorine D phosphorus Your answer [1] 10 The equation for the complete combustion of propene, C3H6, is shown below. C3H6(g) + 4½O2(g) → 3CO2(g) + 3H2O(l) Standard enthalpy changes of formation, ∆f Ho, are shown in the table. Compound ∆f Ho /kJmol–1 C3H6(g) +20 O2(g) 0 CO2(g) –394 H2O(l) –286 What is the standard enthalpy change of combustion of C3H6(g), in kJmol–1? A –2060 B –700 C +700 D +2060 Your answer [1] 6 © OCR 2021 11 The Boltzmann distributions below show a gas at two different temperatures. Which Boltzmann distribution shows the dotted curve at a higher temperature? A number of molecules energy B number of molecules energy C number of molecules energy D number of molecules energy Your answer [1] 7 © OCR 2021 Turn over 12 Which statement about dynamic equilibrium is not correct? A A catalyst increases the rate of both forward and reverse reactions by the same amount. B Dynamic equilibrium exists only in a closed system. C The concentrations of the reactants and products are equal. D The rate of the forward reaction is equal to the rate of the reverse reaction. Your answer [1] 13 What is the number of unsaturated isomers (structural and stereoisomers) that have the molecular formula C4H8? A 3 B 4 C 5 D 6 Your answer [1] 14 What do curly arrows always show in reaction mechanisms? A Movement of one electron. B Movement of a pair of electrons. C Movement of a lone pair of electrons. D Movement of the electrons in a covalent bond. Your answer [1] 8 © OCR 2021 15 Which structural isomer of C7H16 has the weakest induced dipole–dipole interactions (London forces)? A 2,3-dimethylpentane B 3-ethylpentane C 2-methylhexane D 2,2,3-trimethylbutane Your answer