RVHS 2026 Prelim P3 QP

RIVER VALLEY HIGH SCHOOL Preliminary Examination CANDIDATE NAME CLASS CENTRE NUMBER S INDEX NUMBER CHEMISTRY 9476/03 Paper 3 Structured Questions 2 hours You must answer on the question paper. You will need: Data booklet INSTRUCTIONS • Section A: answer all questions. • Section B: answer one question. • Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs. • Write your name, centre number and index number in the boxes at the top of the page. • Write your answer to each question in the space provided. • Do not use an erasable pen. Do not use correction fluid or tape. • You may use an approved calculator. INFORMATION • The total mark for this paper is 75. • The number of marks for each question or part question is shown in brackets [ ]. For Examiner’s Use Question Number 1 2 3 4 5 Marks 16 24 15 20 20 significant figures units Total 75 This document has 24 pages. Any blank pages are indicated. [Turn over

2 River Valley High School 9476/03/Prelims/26 Section A Answer all the questions in this section in the spaces provided. 1 (a) The nitrates, carbonates and hydroxides of Group 2 elements can undergo thermal decomposition. (i) During the thermal decomposition of Group 2 nitrates, a metal oxide, oxygen and a brown gas are produced. Write a balanced equation, with state symbols, for the decomposition of calcium nitrate. …………………………………………………………………………..................... [1] (ii) The nitrates of lead and zinc can undergo thermal dec omposition similar to calcium nitrate. The decomposition temperatures of the three nitrates are given in Table 1.1. Table 1.1 compound decomposition temperature/ C lead(II) nitrate, Pb(NO3)2 290 calcium nitrate, Ca(NO3)2 132 zinc nitrate, Zn(NO3)2 105 Explain, with reference to the Data Booklet, the trend in the decomposition temperatures of the metal nitrates in Table 1.1. …………………………………………………………………………........................... …………………………………………………………………………........................... …………………………………………………………………………........................... …………………………………………………………………………........................... …………………………………………………………………………........................... …………………………………………………………………………........................... …………………………………………………………………………........................... …………………………………………………………………………........................... …………………………………………………………………………........................... …………………………………………………………………………..................... [3]

3 River Valley High School 9476/03/Prelims/26 [Turn over (b) Calcium phosphate, Ca3(PO4)2, is a mineral found in our bones. Table 1.2 gives data relevant to the question. Table 1.2 value/ kJ mol–1 standard enthalpy change of atomisation of Ca(s) +178 standard enthalpy change of formation of Ca3(PO4)2(s) −4175 lattice energy of Ca3(PO4)2(s) −10520 standard enthalpy change of hydration of Ca2+(g) −1562 standard enthalpy change of hydration of PO43–(g) −2876 (i) Use the data from Table 1.2 and the Data Booklet to calculate the standard enthalpy change of formation of PO43–(g). [2] (ii) Define the term standard enthalpy change of solution. …………………………………………………………………………........................... …………………………………………………………………………........................... …………………………………………………………………………..................... [1]

4 River Valley High School 9476/03/Prelims/26 (iii) The standard enthalpy change of solution of Ca3(PO4)2 can also be calculated using the data in Table 1.2. Calculate the standard enthalpy change of solution of Ca3(PO4)2. [1] (iv) Deduce the order of lattice energy, in decreasing magnitude, of Ca3(PO4)2, Ca3N2 and CaSO4. Explain your answer. …………………………………………………………………………........................... …………………………………………………………………………........................... …………………………………………………………………………........................... …………………………………………………………………………........................... …………………………………………………………………………........................... …………………………………………………………………………..................... [2] (c) The distinctive smell of swimming pool water is attributed to various types of chloramines, such as NH2Cl, NHCl2 and NCl3. These chloramines are formed from the reaction between ammonia and hypochlorous acid, HClO. (i) At a temperature of 70 .0 C and a pressure of 1.20 atm, 0.400 g of a gaseous mixture containing NH2Cl, NHCl2 and NCl3 takes up a volume of 150 cm3. Calculate the average molar mass of the sample. [2]

5 River Valley High School 9476/03/Prelims/26 [Turn over (ii) Explain why NCl3 gas behaves less ideally than NH3 gas. …………………………………………………………………………........................... …………………………………………………………………………........................... …………………………………………………………………………..................... [1] (iii) NCl3 can be removed by channelling swimming pool water through an ultraviolet (UV) disinfection system, producing chlorine gas as shown by the equation below. 2NCl3(l) → N2(g) + 3Cl2(g) ∆H = +184 kJ mol−1 Explain why the standard entropy change of this reaction is positive. ………………………………………….……………………………….......................... ……………………………………….………………………………….................... [1] (iv) Using the information in (c)(iii), explain whether a lower or higher temperature will favour the removal of NCl3 in swimming pool. ………………………………………….……………………………….......................... ………………………………………….……………………………….......................... ………………………………………….……………………………….......................... ……………………………………….………………………………….................... [2] [Total: 16]

6 River Valley High School 9476/03/Prelims/26 2 Use of the Data Booklet is relevant to this question. The hydrogen fuel cell presents a solution to generate clean and sustainable energy for static based application. It also boasts a very high energy efficiency, where up to 75% of energy used could be put to useful work. Storage and transport of hydrogen gas, however, is challenging, and it presents a significant barrier in the development and adoption of hydrogen fuel cell for practical applications. (a) Suggest why hydrogen gas is challenging to store and transport. ………………………………………………………………………………………………..…… ……………………………………………………………………………………………...… [1] The Direct Methanol Fuel Cell (DMFC) addresses the hydrogen fuel portability issue by feeding liquid methanol directly into an acidic proton-exchange membrane cell. Fig. 2.1 (b) (i) State the direction of electron flow in the external circuit. ………………………………………………………………………………………… [1] (ii) Construct the balanced half -equation at electrode X and deduce the overall balanced cell equation for the DMFC. …………………………………………………………………………………………….. ………………………………………………………………………………………..…… ………………………………………………………………………………………… [2]

7 River Valley High School 9476/03/Prelims/26 [Turn over (iii) Given that the standard cell potential for this cell is +1.21 V, calculate the standard electrode potential for the half-cell containing methanol. [1] (iv) A DMFC produced an average of 4.34 A of current during its operation. Calculate the volume of CO 2(g) produced in one hour at room temperature and pressure. [2] (v) Predict and explain the effect on the electromotive force generated if pure oxygen is used at electrode Y. …………………………………………………………………………………………….. …………………………………………………………………………………………….. …………………………………………………………………………………………….. …………………………………………………………………………………………….. ………………………………………………………………………………………..…… ………………………………………………………………………………………… [2] (c) The overall reaction taking place inside the fuel cell is similar to the complete combustion of liquid methanol. Th