2025 DHS H1 Chem Prelim Paper 1 QP

© DHS 2025 8873/01 [Turn over Name: Centre/Index Number: Class: DUNMAN HIGH SCHOOL Preliminary Examination Year 6 H1 CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet Data Booklet 8873/01 25 September 2025 1 hour READ THESE INSTRUCTIONS FIRST Write your centre number, index number, name and class at the top of this page. Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. There are thirty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet. Read the instructions on the Answer Sheet very carefully. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. The use of an approved scientific calculator is expected, where appropriate. This document consists of 11 printed pages and 1 blank page.

2 © DHS 2025 8873/01 1 Use of the Data Booklet is relevant to this question A 5 g sample of a diatomic gas was found to contain 3.76  1022 atoms. What is the relative molecular mass of this gas? A 40 B 80 C 120 D 160 2 In two separate experiments, a beam of alpha particles ( 4He2+) and a beam of charged particles X were fired with equal velocities into an electric field. + _ beam of particles The angle of deflection of the charged particles, 4He2+ and X, was found to be +1  and +6 respectively. Which statement is correct? A X is negatively charged. B X travels in a straight path towards one of the charged plates. C X could be a 12C+ ion. D None of the above. 3 Use of the Data Booklet is relevant to this question. Which of the following electronic configurations represents an element that forms a simple ion with a charge of –3? A 1s22s22p63s23p1 B 1s22s22p63s23p3 C 1s22s22p63s23p63d14s2 D 1s22s22p63s23p63d74s2

3 © DHS 2025 8873/01 [Turn over 4 Use of the Data Booklet is relevant to this question. W is an isotope of an element. An isotope of strontium has a nucleon number of 84 and the same number of neutrons in the nucleus as the isotope W. The species Sr2+ and W contain the same number of electrons. What is the nucleon number of W? A 80 B 82 C 83 D 84 5 Use of the Data Booklet is relevant to this question. Which particle contains a single unpaired electron? A Cr atom B Cu+ ion C H2S molecule D NO2 molecule 6 The molecules O=C=O, S=C=S and O=C=S are all linear. Which statements are correct? 1 The molecules all contain polar covalent bonds. 2 Only O=C=S has permanent dipole–permanent dipole interactions. 3 O=C=S has stronger instantaneous dipole–induced dipole interactions than S=C=S. A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and 3

4 © DHS 2025 8873/01 7 Which row correctly describes the structure and bonding present in the solid lattice of the given substance? substance structure bonding A ice giant molecular covalent and hydrogen bonding B iodine simple molecular covalent bonding and permanent dipoles C sodium nitrate giant ionic ionic and covalent bonding D manganese giant metallic ionic bonding 8 Which statement best explains why the boiling point of CH 3CH2CH2NH2 is higher than that of (CH3)3N? A CH3CH2CH2NH2 molecule is polar while (CH 3)3N molecule is non -polar. B There are more electrons in CH 3CH2CH2NH2 molecule than (CH 3)3N molecule. C The surface area of CH 3CH2CH2NH2 molecule is larger than that of (CH 3)3N molecule. D There are hydrogen bonds between CH 3CH2CH2NH2 molecules but not between (CH3)3N molecules. 9 Carbon disulfide vapour burns in oxygen according to the following equation. CS2(g) + 3O2(g) → CO2(g) + 2SO2(g) 10 cm3 of carbon disulfide was burned in 50 cm 3 of oxygen. After measuring the volume of gas remaining, the resulting mixture was treated with an excess of aqueous sodium hydroxide and the volume of gas measured again. What were the measured volumes? volume of gas after burning / cm3 volume of gas after adding NaOH(aq) / cm3 A 30 0 B 30 20 C 50 20 D 50 40

5 © DHS 2025 8873/01 [Turn over 10 0.00200 mol of nitrate ions was reduced by 30.0 cm3 of 0.200 mol dm–3 iron(II) sulfate and an iron(III) product was formed. What is a possible identity of the nitrogen–containing product? A N2 B NO C NO2– D NO2 11 Use of the Data Booklet is relevant to this question. When acidified potassium dichromate( VI) acts as an oxidising agent, the Cr 2O72– ion is reduced to Cr3+. Ethanol is oxidised to ethanoic acid as shown. CH3CH2OH + H2O → CH3COOH + 4H+ + 4e– How many moles of ethanol molecules are oxidised by 1 mol of potassium dichromate(VI)? A 0.67 B 0.75 C 1.33 D 1.50 12 An energy cycle is shown below. C(s) + O2(g) CO2(g) CO(g) + O2(g) 1 2 DH Which data values are required to calculate DH? 1 the standard enthalpy change of formation of oxygen 2 the standard enthalpy change of formation of carbon dioxide 3 the standard enthalpy change of combustion of carbon monoxide A 1 and 2 only B 2 and 3 only C 1 and 3 only D 1, 2 and 3

6 © DHS 2025 8873/01 13 Use of the Data Booklet is relevant to this question. The steam reforming process is described by the equation below. CH4(g) + H2O(g) → CO(g) + 3H2(g) What is the enthalpy change of the reaction? A +175 kJ mol−1 B −175 kJ mol−1 C +892 kJ mol−1 D −892 kJ mol−1 14 Which equation corresponds to the stated enthalpy change? equation enthalpy change A P(s) + 5 2 Cl2(g) → PCl5(s) formation B H+(g) + OH−(g) → H2O(l) neutralisation C Na2O(s) → 2Na+(g) + O2−(g) lattice energy D 2Cl(g) → Cl2(g) bond energy 15 The rate of removal of aspirin, a pain–killer drug, from the body follows a first–order reaction. It takes 6.0 hours for 87.5% of aspirin to be removed from the body. How much time does it take for 50% of aspirin to be removed from the body? A 120 min B 180 min C 206 min D 240 min 16 Bromic acid and hydrobromic acid undergo a redox reaction to form bromine. HBrO3 + 5HBr → 3H2O + 3Br2 The rate equation is shown below. rate = k[BrO3–][Br–][H+]2 What are the units of the rate constant, k? A mol–4 dm12 s–1 B mol–3 dm9 s–1 C mol–2 dm6 s–1 D mol dm–3 s–1

7 © DHS 2025 8873/01 [Turn over 17 Which statement is correct for the equilibrium below? N2(g) + 3H2(g) ⇌ 2NH3(g) DH < 0 change effect on position of equilibrium effect on Kc A addition of catalyst shifts right no change B addition of ammonia gas shifts left decreases C decrease in temperature shifts right increases D increase in pressure of vessel shifts left no change 18 When a mixture of 2 mol of sulfur dioxide and 1 mol of oxygen is allowed to reach equilibrium at a given temperature, the mixture is found to contain x mol of sulfur dioxide. 2SO2(g) + O2(g) ⇌ 2SO3(g) What are the amounts of the three species at equilibrium? SO2 / mol O2 / mol SO3 / mol A x x/2 2 – x B x 1 – x x C x x/2 x D x 1 – x 2 – x 19 In which reaction is the underlined substance in the equation acting as a Brønsted–Lowry base? A CH3COOH(aq) + Na( s) → CH3COONa(aq) + 1 2H2(g) B Na2O(s) + H2O(l) → 2NaOH(aq) C CH3NH2(g) + HC l(g) → CH3NH3Cl(s) D 2KOH(aq) + H2SO4(aq) → K2SO4(aq) + 2H 2O(l)

8 © DHS 2025 8873/01 20 25 cm3 of 0.1 mol dm–3 aqueous sulfuric acid was titrated with aqueous ammonia of the same concentration and the following graph is obtained. (The graph is not drawn to scale.) Which state