NYJC 2020 Prelim 9729 P1

NANYANG JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CHEMISTRY 9729/01 Paper 1 Multiple Choice 18 September 2020 1 hour Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class and tutor’s name on the Answer Sheet in the spaces provided unless this has been done for you. 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 16 printed pages and 0 blank page. [Turn over

2 H2 Chemistry 9729/01 NYJC J2/20 PX 1 Use of the Data Booklet is relevant to this question. A typical solid fertiliser for use with household plants and shrubs contains the elements N, P and K in the ratio of 15 g : 30 g : 15 g per 100 g of fertiliser. The recommended usage of fertiliser is 14 g of fertiliser per 5 dm3 of water. What is the concentration of nitrogen atoms in this solution? A 0.015 mol dm–3 B 0.030 mol dm–3 C 0.075 mol dm–3 D 0.149 mol dm–3 2 Beams of charged particles are deflected by an electric field. In an experiment, protons are deflected by an angle of +15 o. In another experiment under identical conditions, particle Y is deflected by an angle of +5 o. What could be the composition of particle Y? no. of protons no. of neutrons no. of electrons A 1 2 1 B 3 3 5 C 4 5 1 D 4 5 3 3 In which pair do the species have different shapes from each other? A BeCl2 and CO2 B BH4– and NH4+ C OF2 and SCl2 D PH3 and SO3

3 H2 Chemistry 9729/01 NYJC J2/20 PX [Turn over 4 Liquids X and Y do not react with one another. They have identical boiling points. When a particular v olume of X is shaken with a similar volume of Y, they form a liquid mixture Z. The average intermolecular forces in liquid Z are stronger than the average of the forces in X and the forces in Y. Which deductions from this information are correct? 1 The mixing of X and Y is exothermic. 2 The vapour pressure of liquid Z will be less than that of either liquid X or liquid Y at the same temperature. 3 The boiling point of liquid Z will be lower than that of either liquid X or liquid Y at the same pressure. A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 only 5 Which graph correctly describes the behaviour of two ideal gases P and Q, both having the same mass, where P has a larger Mr than Q? A B C D T / oC p Q P T / oC p Q P p V pV constant T Q P p pV constant T P Q constant V constant V

4 H2 Chemistry 9729/01 NYJC J2/20 PX 6 Use of the Data Booklet is relevant to this question. A butane burner is used to heat water. The Mr of butane is 58.  Hʅ c of butane is –2877 kJ mol–1.  250 g of water is heated from 12 °C to 100 °C.  The burner transfers 47% of the heat released from the burning fuel to the water. Assume that the butane undergoes complete combustion and none of the water evaporates. What is the minimum mass of butane that must be burnt? A 0.071 g B 1.85 g C 3.94 g D 4.48 g 7 Sulfur can be oxidised in two ways. S(s) + O2(g)  SO2(g) H = –296.5 kJ mol–1 2S(s) + 3O2(g)  2SO3(g) H = –791.4 kJ mol–1 Sulfur trioxide can be made from sulfur dioxide and oxygen. 2SO2(g) + O2(g)  2SO3(g) What is the standard enthalpy change for this reaction? A –1384.4 kJ mol–1 B –989.8 kJ mol–1 C –494.9 kJ mol–1 D –198.4 kJ mol–1

5 H2 Chemistry 9729/01 NYJC J2/20 PX [Turn over 8 After the closure of a chemical plant in Switzerland, the reaction bet ween 1-bromobutane and hydrogen sulfide ions (HS –) was found to be taking place in the ground. The following results were obtained. Initial concentration of 1-bromobutane / mol dm–3 Initial concentration of hydrogen sulfide ions / mol dm–3 Initial rate of reaction / mol dm–3 s–1 0.1 0.2 0.3 0.1 0.1 0.1 0.1 0.1 0.2 0.3 1.5 × 10–5 3.0 × 10–5 4.5 × 10–5 3.0 × 10–5 4.5 × 10–5 Which of the following statements is correct? A The reaction is first order with respect to 1-bromobutane only. B The reaction is zero order with respect to hydrogen sulfide ions. C Both 1 -bromobutane and hydrogen sulfide ions are involved in the rate - determining step. D The rate constant is 1.5 × 10–5 mol–1 dm3 s–1.

6 H2 Chemistry 9729/01 NYJC J2/20 PX 9 The diagram shows the distribution of kinetic energies in a sample of gas at a temperature T1. The activation energy for an uncatalysed reaction of this gas, Ea(uncat), is shown. Which diagram correctly shows the new distribution and new activation energy, Ea(cat), when the temperature is increased to T2, and a catalyst is used that increases the rate of the reaction? A B C D Proportion of molecules with a given energy kinetic energy E kinetic energy E Proportion of molecules with a given energy Proportion of molecules with a given energy kinetic energy E kinetic energy E kinetic energy E Proportion of molecules with a given energy Proportion of molecules with a given energy

7 H2 Chemistry 9729/01 NYJC J2/20 PX [Turn over 10 A pure sample of NO 2(g) is introduced into an evacuated vessel. The vessel, of constant volume, is heated to a constant tempera ture such that the equilibrium below is established. 2NO2(g) ⇌ 2NO(g) + O2(g) The value of the pressure p is then found to be 30 % greater than if only NO 2(g) were present. What is the mole fraction, x, of oxygen in this equilibrium mixture? A 0.17 B 0.23 C 0.37 D 0.43 11 The percentage yield and rate of chemica l reactions is an important consideration in industrial applications like the Haber Process. N2 + 3H2 ∏ 2NH3 Which of the following changes made to the Haber Process increases both the rate and percentage yield? Option Change made 1 Increase in temperature 2 Add a catalyst 3 Increase in pressure A 1 and 2 B 1 and 3 C 3 only D all of the above

8 H2 Chemistry 9729/01 NYJC J2/20 PX 12 In which reaction does ammonia behave as a Brønsted-Lowry base? A NH3 + H2O + CO2  (NH4)HCO3 B NH3 + CH3CH2Br  CH3CH2NH2 + HBr C NH3 + HNO2  N2 + 2H2O D NH3 + NaH  NaNH2 + H2 13 The table gives the concentrations and pH values of the aqueous solutions of two compounds, X and Y. Either compound could be an acid or a base. X Y concentration pH 2 mol dm–3 6 2 mol dm–3 9 Which of the following statements are true? 1 Student P concluded that X is a strong acid. 2 Student Q concluded that Y is a strong base. 3 Student R concluded that X is a weak acid. 4 Student S concluded that the extent of dissociation is smaller in X(aq) than in Y(aq). A 3 and 4 B 3 only C 2 and 4 D 1 and 2 only

9 H2 Chemistry 9729/01 NYJC J2/20 PX [Turn over 14 Use of the Data Booklet is relevant to this question. The standard cell potentials for the redox equilibria of aqueous vanadium - containing ions and the colours of these ions are given below. VO2+ + 2H+ + e Ý H2O + VO2+ Eʅ = +1.00 V yellow blue VO2+ + 2H+ + e Ý H2O + V3+ Eʅ = +0.34 V blue green V3+ + e Ý V2+ Eʅ = –0.26 V green purple What is likely to be the final colour when excess metallic zinc is added to a solution containing VO2+? A yellow B blue C green D purple

10 H2 Chemistry 9729/01 NYJC J2/20 PX 15 Use of the Data Booklet is relevant to this question. The following