2021 RVHS Prelim P1 Ans

River Valley High School 8873/01/PRELIMS/21 2021 Preliminary Examination [Turn over RIVER VALLEY HIGH SCHOOL JC 2 PRELIMINARY EXAMINATION CANDIDATE NAME CLASS 2 0 J CENTRE NUMBER S INDEX NUMBER H1 CHEMISTRY 8873/01 Paper 1 Multiple Choice 23 Sep 2021 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, centre number and index number on the Answer Sheet in the spaces provided. 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 14 printed pages.

2 River Valley High School 8873/01/PRELIMS/21 2021 Preliminary Examination 1 When potassium chlorate( V) KC lO3, is heated at its melting point, it disproportionates to potassium chlorate(VII) KClO4, and potassium chloride. What is the maximum number of moles of potassium chlorate( VII) which could be produced from 0.200 mol of potassium chlorate(V)? A 0.200 B 0.150 C 0.100 D 0.0500 2 Methane was burned in an incorrectly adjusted Bunsen burner. The methane was converted into a mixture of carbon dioxide and carbon monoxide in the ratio 99:1, together with water vapour. What will be the volume of oxygen consumed when y dm3 of methane is burned? A 3( 2y 0.01y ) dm B 30.01y( 2y ) dm2 C 30.01y( y ) dm2 D 3( y 0.01y ) dm 3 Use of the Data Booklet is relevant to this question. Iron in the form of magnetite, Fe 3O4, is extracted from ores in iron mines. The ore contains 69.9% by mass of iron. What percentage of the ore contains Fe3O4 by mass, if it is the only iron-containing component present? A 3.40% B 69.9% C 96.6% D 100%

3 River Valley High School 8873/01/PRELIMS/21 2021 Preliminary Examination [Turn over 4 Use of the Data Booklet is relevant to this question. The table shows the fifth, sixth, seventh, eighth and ninth ionisation energies of three elements in the third period. Ionisation energy/ kJ mol‒1 5th 6th 7th 8th 9th Element A 6274 21267 25431 29872 35905 Element B 7004 8496 27107 31719 36621 Element D 6542 9362 11018 33604 38600 Which statements are correct? 1 The first ionisation energy of A is lower than that of B. 2 The atom of element A will be isoelectronic with D2+. 3 A and D forms an ionic solid AD3. A 1 and 3 only B 2 and 3 only C 1 only D 2 only 5 In which order are the electrons lost in forming Ga4+ ion? 1st 2nd 3rd 4th A 3d 4p 4s 4s B 3d 4s 4s 4p C 4p 4s 3d 3d D 4p 4s 4s 3d 6 Which of the following statements is correct? A Dative bonding is present in the NH4+ ion. B AlCl3 is able to conduct electricity because it is ionic. C In MgO(s), one Mg 2+ ion can form electrostatic forces of attraction with only one O2 ion. D SiC has a giant molecular structure whereas SiO 2 has a simple molecular structure.

4 River Valley High School 8873/01/PRELIMS/21 2021 Preliminary Examination 7 Which pair of liquids, when mixed, will give out heat? A CH2Cl2 and CH3COCH2CH3 B CH2Cl2 and C6H12 C CF4 and COCl2 D CCl4 and C10H21OH 8 A molecule of BCl3 is planar, whereas a molecule of PH3 is pyramidal. Which statements are responsible for the difference in shapes? 1 The repulsion between chlorine atoms is greater than that between hydrogen atoms. 2 The boron atom in BC l3 has six electrons in its valence shell, whereas the phosphorus atom in PH3 has eight. 3 The atomic radius of phosphorus is greater than that of boron. A 1 only B 2 only C 1 and 3 only D 2 and 3 only 9 Which of the following equations best define the term bond energy of CH bond? A CH3CH2CH2CH3(l) → 4C(s) + 5H2(g) B CH3CH2CH3(l) → 3C(s) + 8H(g) C CH3CH3(g) → 2C(g) + 6H(g) D 1 4 CH4(g) → 1 4 C(g) + H(g)

5 River Valley High School 8873/01/PRELIMS/21 2021 Preliminary Examination [Turn over 10 When water is stirred with glucose, strong hydrogen bonds are initially formed between glucose molecules and water molecules. As more water is added, these hydrogen bonds are broken. Which of these graphs best represents the observed temperature changes? A C B D 11 Aqueous sodium chlorate(I), NaOCl, is used to keep swimming pool water free of harmful bacteria. It is the HOCl molecules formed when NaOCl reacts with water that kill bacteria. OCl(aq) + H2O  OH(aq) + HOCl(aq) The OCl ion is broken down by ultra-violet light from the sun. OCl(aq) + uv light → Cl(aq) + 1 2 O2(g) What could be done to maintain the highest concentration of HOCl? A acidify the pool water B add a solution of chloride ions C add a solution of hydroxide ions D bubble air through the water temperature volume of water added temperature volume of water added temperature volume of water added temperature volume of water added

6 River Valley High School 8873/01/PRELIMS/21 2021 Preliminary Examination 12 The equilibrium constant Kc for the reaction G(g) + 2H(g) ⇌ J(g) is found to vary with temperature T as shown in the diagram below. Which of the following statements about the reaction is correct? A The forward reaction is exothermic. B The yield will decrease at higher pressure. C Addition of a catalyst will cause the graph to be steeper at higher temperature. D The equilibrium mixture contains a higher proportion of J at higher temperature. 13 The gases, X2 and Y2 react as follows, X2(g) + Y2(g)  2XY(g) A mixture containing 1.0 mol of X2 and 0.8 mol of Y2 is heated in a closed container and the reaction is allowed to reach equilibrium. The graph below shows the variation of the number of moles of each gas with time. What is the numerical value of Kc? A 0.0750 B 0.150 C 6.67 D 13.3

7 River Valley High School 8873/01/PRELIMS/21 2021 Preliminary Examination [Turn over 14 Nitrogen oxide reacts with hydrogen gas as shown in the equation below. 2NO(g) + 2H2(g)  N2(g) + 2H2O(g) The reaction was determined to be second order with respect to NO and first order with respect to H2. In an experiment, 2.0 mol dm–3 of excess NO was used to react with H 2, the concentration of H 2 decreased to 6.25% of its original value in 24 minutes. How many minutes will it take for the concentration of H 2 to decrease to 6.25% of its original value if the experiment was repeate d using an excess of 4.0 mol dm –3 of NO? A 1.5 B 4.5 C 6.0 D 9.0 15 The diagram shows the Maxwell -Boltzmann energy distribution curves for molecules of a sample of a gas at two different temperatures. Which letter on the axes represents the proportion of molecules with the most probable energy at the lower temperature?

8 River Valley High School 8873/01/PRELIMS/21 2021 Preliminary Examination 16 The value of the ionic product of water, Kw, varies with temperature. temperature/ C Kw / mol2 dm6 25 1.0 × 1014 62 1.0 × 1013 What can be deduced from this information? A Water is acidic at 62 C. B The ionic dissociation of water increases by a factor of 5 between 25 C and 62 C. C The ionic dissociation of water is an endothermic process. D Concentration of OH at 62 C is 5.0 × 1014 mol dm3. 17 The following reaction occurs when light is shone for a fixed period into a solution o