YuYing WA1 2025 Chemistry

NAME YUYING SECONDARY SCHOOL WEIGHTED ASSESSMENT (TERM 1) Secondary 4 CLASS REG.NOD CHEMISTRY Candidates answer on the Question Paper. Additional Materials: Nil. READ THESE INSTRUCTIONS FIRST Write your name, class and register number on the work 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, highlighters, glue or correction fluid. Section A There are ten questions in this section. Answer all questions. For each question there are four possible answers A, B, C and D. 6092 11 February 2025 50 minutes Setter: Miss Ng Yun Xuan Choose the one you consider correct and record your choice in the spaces provided on the question paper. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Section 8 Answer all questions. Write your answers in the spaces provided on the question paper. The use of an approved calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. A copy of the Periodic Table is printed on page 11. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ J at the end of each question or part question. For Examiners' Use Total This document consists of 11 printed pages.

1 2 section A . • s in this section. Answer all the quest10~ tion is 10. The total mark for this sec . 'd hydrogen and oxygen. . carbon d1ox1 e, The gas jars shown below contain the gases carbon dioxide hydrogen oxygen Which of the following can be used to identify the gases in each jar? A Universal Indicator B a lighted splint C aqueous calcium hydroxide D moist blue litmus paper 2 Aqueous ammonia is added in excess to a solution containing a mixture of calcium chloride and copper(II) chloride. What will be observed? A A blue precipitate forms in a colourless solution. B A white precipitate forms in a dark blue solution. C A mixture of blue and white precipitates form. D The solution turns dark blue. 3 When testing for a sulfate ion using barium nitrate, the solution must be acidified with dilute nitric acid. What is the purpose of the nitric acid? A to act as a catalyst B to oxidise the sulfate ion C to prevent the precipitation of barium carbonate I D to prevent the decomposition of any barium sulfate formed )

4 5 3 . . alt X and boiled •. ~o An excess of sodium hydroxide 1s added to an aqueous solution of 5ft luminium foil 1s b b . . I • n off a er a 0 serva le change seen. Ho\J1ever, ammonia gas 1s on Y give added to the hot solution. What could salt X be? A ammonium nitrate B sodium nitrate C calcium chloride D ammonium chloride . . . B followed by dilute nitric acid. The In an experiment, solution A was added t? ~olutifon 'd hanges with the addition of the graph below shows how the mass of prec1p1tate orme • c different solutions. mass of precipitate / g total volume of tlL..._ ______ --:t;------~ solutions added to solution B / cm3 addition of addition of dilute nitric solution A acid Which of the following would produce the graph shown? solution A ions present in solution B A aqueous silver nitrate sulfate and carbonate ions B aqueous silver nitrate sulfate ions only C aqueous barium nitrate sulfate and carbonate ions D aqueous barium nitrate sulfate ions only 6 Which of the following salts could be prepared by the titration method? A sodium sulfate B copper(II) chloride C lithium nitrate D zinc sulfate ( )

7 4 The table shows the solubility of three unknown salts in cold water. salt M carbonate M chloride M sulfate What could substance M be? A aluminium B ammonium C barium D calcium solubility in cold water soluble soluble soluble ·- I 8 Which of the following salts is best prepared using the reagents listed? 9 name of salt reagents used A potassium nitrate potassium hydroxide + dilute nitric acid 8 calcium sulfate calcium carbonate + dilute sulfuric acid C lead(I I) chloride lead(II) sulfate + dilute hydrochloric acid D sodium sulfate sodium metal + dilute sulfuric acid / Lead chromate(VI) is an insoluble salt which can be used as a yellow paint pigment. Which of the following can be reacted with a solution of potassium chromate(VI) to form lead chromate(VI)? A lead(! I) carbonate 8 lead(I I) sulfate C lead(I I) chloride D lead(I I) nitrate 10 Given a supply of barium carbonate, copper(I I) carbon·ate, dilute nitric1 acid and aqueous sodium hydroxide, how many different insoluble salts could be prepared? A 0 8 1 C 2 D 3 \

r, ( 5 Section B Answer all the questions in this section. The total mark for this section is 30. 1 S?lution J contains the nitrate salts of four cations. The figure below shows the separation of all the cations in solution J. I solution J containing cu:+, Pe(+. Pb2•, Zn2• J Stage 1: add dilute HC land filter ~, • t precipitate L I solution ~ • mixed precipitate M Stage 2: add e xcess ter aq NaOH and fH i l solution Q Stage 3: add aq NH3 and filter t precipitate R l solution U I ( a) Name the precipltat~ L. . . 7' -........................ . 2 (b) State the chemical formula of tM or~cipitate in M pvtiich has a lower relative molecular mass ( c) Give the chemic✓,;:}mula of the Ca~t is present in solution Q. ........................................ (d) State the colour~ solu~ion ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....... . (e) f ~rit~ bal_anye~nic equati~n fo~ ih~ formation of precipita!e R. ............... [ 1 ] [ 1 ] [ 1 ] [ 1 ] [ 2 ]

6 (f) Name another acid that can replace dilute hydrochloric acid in 5tage 1 to produce similar result. Explain your answer. , (g) Briefly describe how you would test for the anion present in solution J. " I • I L [ 2 ] [Total: 1 O] ~ 2 A student carried out some tests using four reagents, A, B, C and D. In each test, he added a different reagent to separate samples of aqueous copper(II) chloride and copper(! I) sulfate. The table below shows the reagents he used for the tests. reagent ,A . zinc powder B acidified aqueous silver nitrate 1 C acidified aqueous barium nitrate D aqueous sodium hydroxide Describe what the student would observe when he adds each of the four reagents to separate fresh samples of aqueous copper(II) chloride and aqueous copper(ll) sulfate . l •, I

3 ( 7 Different salts were made by reacting an excess of a carbonate X with an acid Y. Unreacted solids were separated by filtration and the salt was recovered from the filtrate by crystallisation. Four experiments were carried out using different combinations of X and Y to prepare salts. The percentage yield of each experiment is given in the table belo\V. experiment X y salt prepared percentage yield of salt I% 1 CuC03 H2S04 CuS04 95 2 ZnCQ3 HNQ3 Zn{NQ3)2 92 3 CaC03 H2S04 CaS04 18 4 A92C03 HCI AgCI < 1 ! I (a) Explain whY, the percentage yields of the salts were low in experiments 3 and 4 ~ --. ~ ~ " ,, &C.. (b) Suggest another pair of re·agents that could be ~n experiment 4 to obtain ~ higher vield of the salt. ', , [ 2 ] . . . . . . . . . . . . . . . . . . . . . . [ 1 ] (c) Write the balanced chemical equation for the ~-h reac 107 at ~ccurred in experiment 1. .,,. , C. r , I .. . .. . .. ... ... [ 2] [Total: 5] )

8 4 (a) A solution of zinc chloride can be prepared from zinc and dilute hydrochloric acid using the following steps. step 1: Add an excess of zinc to warm dilute hydrochloric acid. step 2: Filter the resulting mixture. (i) Explain why an excess of zinc is added in step 1. I I I • I . . . "' .... ··················································'~ (ii) State one observation to show that zinc is in excess. I • I t I I t I t t I I I I I I I I I I ♦ I I I ., . • . I I I I I I I I I I I I I I e I t I I I I I I I I I I \..• .. - (iii) Descr