ACJC H1 CHEM MCQ

ANGLO-CHINESE JUNIOR COLLEGE DEPARTMENT OF CHEMISTRY Preliminary Examination CHEMISTRY 8872/01 Higher 1 Paper 1 Multiple Choice 24 August 2017 50 minutes Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluids. Write your name, index number and tutorial class 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. 8872/01/Prelim/17 ANGLO-CHINESE JUNIOR COLLEGE © ACJC 2017 Department of Chemistry [Turn over

2 © ACJC 2017 8872/01/Prelims/17 [Turn over Section A For each question there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 Ether has the formula, CH3OCH3. In a sample of ether, 8.7 % contains the 18O isotope, with the rest contains the 16O isotope. What is the relative molecular mass of ether in this sample? A 46.2 B 46.8 C 47.2 D 47.8 2 Copper reacts with dilute nitric acid to produce nitrogen dioxide gas. The balanced ionic equation is given. Cu + 2H + + 2HNO3  Cu2+ + 2NO2 + 2H2O Which of the following is correct? Oxidation state of N in Role of copper HNO 3 NO 2 A +5 -3 Reducing agent B +5 +4 Reducing agent C -5 -3 Oxidising agent D -5 +4 Oxidising agent

3 © ACJC 2017 8872/01/Prelims/17 [Turn over 3 10 cm 3 of propane was completely burnt in x cm3 of excess oxygen. After cooling to room temperature, the volume of the residual gas was 60 cm 3. The residual gas was passed through aqueous sodium hydroxide was passed through and the volume reduced to y cm3. Which of the following is correct? x y A 50 30 B 60 20 C 70 20 D 80 30 4 An organic compound with the formula C xHyO2 has undergone incomplete combustion, producing carbon dioxide and carbon monoxide in the ratio of 99 : 1. The equation may be represented as follows: CxHyO2 + a O2  b CO + c CO2 + 0.5y H2O a, b and c can be expressed in terms of x and y. Which of the following is correct? a b c A 99x + 0.5x + 0.25y - 1 x 99x B 99x + 0.5x + 0.25y x 99x C 0.99x + 0.005x + 0.25y- 1 0.01x 0.99x D 0.99x + 0.005x + 0.25y 0.01x 0.99x

4 © ACJC 2017 8872/01/Prelims/17 [Turn over 5 Use of the Data Booklet is relevant to this question. The components of a 100 g sample of fertilizer is as shown in the table below: Element Mass / g N 15 P 30 K 15 Other Elements 40 The recommended usage of fertilizer is 14 g of fertilizer per 5 dm3 of water. What is the concentration of nitrogen atoms in this recommended solution? A 0.03 mol dm-3 B 0.15 mol dm-3 C 0.42 mol dm-3 D 0.75 mol dm-3 6 The elements X and Y are in Group 16 and 17 respectively in the same period. Which of the following statements regarding X and Y is most likely to be true? A Y has more unpaired electrons than X. B Y atom is bigger than X atom. C X is more electronegative than Y. D The first ionisation energy of X will likely be less endothermic than that of Y.

5 © ACJC 2017 8872/01/Prelims/17 [Turn over 7 The table gives the successive ionisation energies for an element X. 1st 2nd 3 rd 4th 5th 6th Ionisation energy/ kJ mol –1 950 1800 2700 4800 6000 12300 What could be the formula of the fluoride of X? A XF B XF2 C XF3 D XF4 8 ‘Dot-and-cross’ diagrams for CO are shown below. Which circle pair of electrons represent a co-ordinate bond? A x x B x x C x x D x x 9 Which of the following molecules is linear and non-polar? A CS2 B SCN C SO2 D SiO2

6 © ACJC 2017 8872/01/Prelims/17 [Turn over 10 Consider the following four compounds. 1 CH 3CH2CH2F 2 CH 3CH2CH2OH 3 CH 3CH2CH2CH3 4 (CH 3)3CH What is the order of increasing boiling points of the compounds (from lowest to highest)? A 2 → 1 → 3 → 4 B 4 → 3 → 2 → 1 C 3 → 1 → 2 → 4 D 4 → 3 → 1 → 2 11 The enthalpy changes for two reactions are given by the equations: 2Cr(s) + 2 3 O2(g)  Cr2O3(s) ∆H = - 1130 kJ mol-1 C(s) + ½ O2(g)  CO(g) ∆H = - 110 kJ mol-1 What is the enthalpy change, in kJ mol-1, for the following reaction? 3C(s) + Cr2O3(s)  2Cr(s) + 3CO(g) A -800 B +800 C -1460 D +1460

7 © ACJC 2017 8872/01/Prelims/17 [Turn over 12 Hydrogencarbonate may react with acid according to the equation below. HCO3–(aq) + H+(aq) H2O(l) + CO2(g) Hθ = +12.7 kJ mol–1 Using the following enthalpy changes of formation provided, what is the standard enthalpy change of formation of H+(aq)? species H  f / kJ mol–1 H2O(l) –285.8 CO2(g) –393.5 HCO3–(aq) –692.0 A –25.4 kJ mol–1 B 0.0 kJ mol–1 C +25.4 kJ mol–1 D +1384 kJ mol–1 13 In an experiment, 70 cm3 of water at 25 ºC was brought to boil by burning butane in excess oxygen. Calculate the volume of butane required if this process is only 85 % efficient. [∆H c (butane) = –2877 kJ mol –1; c = 4.2 J g –1 K–1; Molar volume of gas under the given conditions = 24 dm3] A 0.0721 dm3 B 0.156 dm3 C 0.184 dm3 D 0.216 dm3 14 Which statement concerning the equilibrium reaction given below is correct? 2CrO 42–(aq) + 2H+(aq) Cr2O72–(aq) + H2O(l) yellow orange A It is a redox reaction. B The equilibrium constant, Kc, has the units of mol-2 dm6. C The colour of the solution change from orange to yellow when pH increases. D The addition of a catalyst will result in an increase in the concentration of Cr2O72–(aq).

8 © ACJC 2017 8872/01/Prelims/17 [Turn over 15 The kinetics of the reaction between iodine and compound J is investigated. 5 10 time / min [I2] 2y [ J ] = 2a [ J ] = a y What conclusions can be drawn from the graphs? A The reaction is second order with respect to compound J because rate of reaction increases by four times when its concentration is increased by two times. B Both iodine and compound J react in equal mole ratio. C The reaction is first order with respect to iodine because half-life is constant. D The overall order of the reaction is 1. 16 X, Y and Z are elements in Period 3 of the Periodic Table. A mixture containing the oxides of X, Y and Z was dissolved in excess dilute sulfuric acid and filtered. The oxide of Z was collected as a residue. When excess dilute sodium hydroxide was added to the filtrate, only a white precipitate of the hydroxide of Y was formed. What are the possible identities of X, Y and Z? X Y Z A Mg Al P B Al Mg P C Mg Al Si D Al Mg Si

9 © ACJC 2017 8872/01/Prelims/17 [Turn over 17 The oxide and chloride of an element X are separately mixed with water. The two resulting solutions have the same effect on litmus solution. What is element X? A Sodium B Magnesium C Aluminum D Phosphorus 18 Which property of benzene is reflected as a consequence of the delocalised electrons present in its molecule? A Benzene is