RVHS_2023_JC2_H2_CM_Prelim_P2_QP

River Valley High School 9729/02/PRELIM/23 [Turn over 2023 Preliminary Examination RIVER VALLEY HIGH SCHOOL JC 2 PRELIMINARY EXAMINATION CANDIDATE NAME CLASS 2 2 J CENTRE NUMBER S INDEX NUMBER H2 CHEMISTRY 9729/02 Paper 2 Structured Questions 13 September 2023 2 hours Candidates answer on the Question Paper. Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your Centre number, index number, class and name on all the work that you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions in the spaces provided on the Question Paper. If additional space is required, you should use the page at the end of this booklet. The question number must be clearly shown. The use of an approved scientific calculator is expected, where appropriate. A Data Booklet is provided. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use Question Number 1 2 3 4 5 6 Marks 12 12 13 7 13 18 significant figures units Total 75 This document consists of 24 printed pages.

2 River Valley High School 9729/02/PRELIM/23 2023 Preliminary Examination 1 (a) Over one million tonnes of chromium are produced in the world each year and about 30% of it is used in electroplating. In an electroplating experiment, as shown by the set up below, an aqueous solution containing chromium( III) sulfate was electrolysed using a piece of pure chromium and the metal object to be electroplated as the electrodes. (i) Identify the anode in this reaction. ……………………..…………………………………………………........ [1] (ii) A square piece of chromium sheet has a dimension of 0.100 m  0.100 m and a depth of 1000 atoms. Assume that each chromium atom occupies a length of 3.00  1012 m, calculate how long it will take for 90.0 % of the chromium sheet to be used when a constant current of 4.00 A is provided. [3] key Chromium(III) sulfate aqueous solution Chromium sheet Power source

3 River Valley High School 9729/02/PRELIM/23 [Turn over 2023 Preliminary Examination (iii) The experiment was repeated using dilute sulfuric acid and a piece of pure aluminium in place of chromium sheet. Explain why the aluminium electrode gained mass. W rite relevant equations to support your answer. …………………………..……………………………………………........ ……………………………..………………………………………………. ………………………..……………………………………………………. ………………………..……………………………………………………. [2] (b) The s uccessive ionisation energies , in kJ mol 1, of an element X are given below. 1012, 1907, 2914, 4964, 6274, 21267, 25431, 29872 (i) With the aid of an equation involving X, explain the term first ionisation energy. …………………………..…………………………………………….....