RVHS Prelim_H1_Chemistry_P2_QP

River Valley High School 8873/02/PRELIMS/25 [Turn over 2025 JC 2 Preliminary Examination RIVER VALLEY HIGH SCHOOL JC 2 PRELIMINARY EXAMINATIONS CANDIDATE NAME CLASS 2 4 J INDEX NUMBER H1 CHEMISTRY 8873/02 Paper 2 Structured Questions 16 September 2025 2 Hours Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST. DO NOT OPEN THIS BOOKLET UNTIL YOU ARE TOLD TO DO SO. Write your name, class and index number in the spaces at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, highlighters, glue or correction fluid. Section A Answer all questions in the spaces provided on the Question Paper. The question number must be clearly shown. Section B Answer one question. 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. This paper consists of 24 printed pages. For Examiner’s Use Paper 1 30 Paper 2 1 11 2 8 3 6 4 10 5 7 6 10 7 8 8 20 9 20 s.f. units Paper 2 80 Total 110

2 River Valley High School 8873/02/PRELIMS/25 2025 JC 2 Preliminary Examination Section A Answer all the questions in this section in the spaces provided. 1 Iron ore deposits are found globally, with significant reserves in Australia, Brazil, Russia, China, and India. A company refining iron ore would only purchase more ores from distributors if the percentage of iron in each ore is >60%. If it is any lower than this, then the cost of refining the ore will be considered expensive. (a) Define the term mole. …………………………………………………………………………………….. …………………………………………………………………………………….. …………………………………………………………………………………….. [1] (b) An experiment was carried out to determine the percentage of iron in a sample of iron ore. A 3.35 g piece of ore was reacted with dilute sulfuric acid, in the absence of air, so that all the iron atoms were converted to iron(II) ions. The resulting solution was made up to 250 cm3. Other substances in the ore do not react and are filtered out of the mixture. A 25.0 cm 3 sample of this iron(II) solution was further acidified with 10.0 cm3 of sulfuric acid and titrated with 0.0250 mol dm−3 purple potassium manganate(VII). 32.00 cm3 of the potassium manganate(VII) solution was required for complete reaction. The relevant half-equations for the reaction are shown below. MnO4– + 8H+ + 5e– → Mn2+ + 4H2O Fe3+ + e– → Fe2+ (i) Write a balanced equation for the reaction between the iron in the ore and the sulfuric acid. ……………………………………………………………………………… [1] (ii) State the role of potassium manganate(VII) in the reaction with the iron(II) solution. Explain your answer in terms of oxidation number. ……………………………………………………………………………… ……………………………………………………………………………… [2]