NYGH 2011-S3BT2-Chem

Class Register Number Name 南洋女子中学校 NANYANG GIRLS' HIGH SCHOOL BLOCK TEST 2 Secondary Three CHEMISTRY 1 hour Thursday 4 August 2011 1015-1115 h READ THESE INSTRUCTIONS FIRST Do not open this booklet until you are told to do so. Write your name, register number and class in the spaces at the top of this page. Section A (Multiple Choice) Section A (15 MCQ) This section consists of 15 multiple choice questions. Choose the best answer and write its letter in the space provided on page 2 of the Question Paper. Section B (Structured) Answer All questions in the spaces provided on the Question Paper. Section C (Free-Response) Answer All questions in the spaces provided on the Question Paper. Submit Sections A, B and C together. INFORMATION FOR CANDIDATES The intended number of marks is given in the brackets [ ] at the end of each question or part question. A copy of the Periodic Table is printed on page 10. TEST TOPICS: ƒ Qualitative Analysis ƒ Acids and Bases ƒ Salt Preparation ƒ Ionic Equations ƒ Mole Concept Examiner’s Use Section A (15 marks) Section B (20 marks) Section C (10 marks) Total (45 marks) Setter: A Siew This document consists of 10 printed pages. NANYANG GIRLS' HIGH SCHOOL [ Turn over]

2011 Secondary Three Block Test 2 Nanyang Girls’ High School Setter: A Siew Chemistry 2 ection A (15 Marks)S (1-15) by filling the answer in the table below.Answer the questions 1 6 11 2 7 12 3 8 13 4 9 14 5 10 15 ection B (20 marks)S n this section in the spaces providedAnswer all questions i 1 In an experiment, a sample of iron powder was oxidized to form a certain the empirical formula of the oxide if it contained 30% by [3] ) .5 mole of the oxide of iron produced in B1(a) completely reacted ) Calculate the number of moles of hydrochloric acid reacted. ] i) rite down a balanced chemical equation for this reaction, ] B oxide of iron. (a) Calculate mass of oxygen. (b 0 with 109.5 g of dilute hydrochloric acid to form a salt of iron and water. (i [2 (i W complete with the state symbols. [2 (ii) escribe the observations that will be obtained when excess ] D aqueous sodium hydroxide was added gradually to the salt of iron obtained from the reaction. [2

2011 Secondary Three Block Test 2 Nanyang Girls’ High School Setter: A Siew Chemistry [Turn Over] 3 2 ) hen nitrogen gas was reacted wit h hydrogen gas at a certain temperature and pressure, ammonia gas was produced. If there were 120 3 i) calculate the mass of nitrogen present in the ammonia gas produced. ] ii) calculate the number of ammonia molecules produced. ] ) he empirical formula of a certain gas is XY2. he relative atomic mass of X and Y are 12 and 1 respectively. e ] i) A sealed cylinder contains 36 dm3 (measured at r.t.p) of the gas mentioned in (b)(i). ] B (a W dm (measured at r.t.p) of ammonia gas produced, (i) determine the mass of ammonia gas produced. [1] (i [1 (i [1 (b T T [1(i) If the relative molecular mass of the gas is 42, determine th molecular formula of the gas. (i Calculate the mass of Y present in the gas. [2

2011 Secondary Three Block Test 2 Nanyang Girls’ High School Setter: A Siew Chemistry 4 3 hen exc de is added gradually to an aqueous solution X, a dirty green precipitate which is insoluble in excess aqueous sodium hydroxide is formed. The reaction also forms aqueous chloride Y. B W ess aqueous sodium hydroxi (a) State the chemical name of aqueous solution X and Y respectively. [2] (b) or every mole of X reacted, 2 moles of Y are formed. Calculate the ass of X reacted if 11.7g of Y is produced. ] END OF SECTION B F m [3

2011 Secondary Three Block Test 2 Nanyang Girls’ High School Setter: A Siew Chemistry [Turn Over] 5 ection C (10 marks)S C1 (a) (i) Name a suitable reagent, which when reacted with dilute hydrochloric acid will give aluminium chloride. [1] (ii) Write the ionic equation for the preparation of aluminium chloride salt in part (a)(i) [1] (b) (i) Name a suitable reagent whic h when reacted with dilute sulfuric acid will give potassium sulfate. [1] (ii) Name the suitable method used to prepare the salt mentioned in part (b)(i) [1] (c) The graph below shows the solubility curves of some salts. (i) With the help of the graph abo ve, describe how a pure dry sample of aluminium chlori de can be obt ained with the proposed reagents in (a)(i). [3] temperature/oC potassium dichromate (VI) sodium fluoride aluminium chloride potassium sulphate solubility per gram of salt in 100 cm3 of water potassium sulfate potassium dichromate(VI)

2011 Secondary Three Block Test 2 Nanyang Girls’ High School Setter: A Siew Chemistry 6 (ii) With the help of the graph above, describe how a dry sample assium sulfate can be obtained from its aqueous solution? Explain your answer. [3] of pot ☺END OF TEST☺

2011 Secondary Three Block Test 2 Nanyang Girls’ High School Setter: A Siew Chemistry [Turn Over] 7 ectio A 5 m rks)S n (1 a hoo e th mos suitable answer and write its letter in the answer table C s e t provi d o agde n P e 2. ed, the anhydrous solid X gives off a gas Y which turns acidifi ichromate(VI) from orange to 1 When heat ed potassium green. The reddish brown residue reacts with dilute acid to form salt and water. What are the identities of X and Y? X Y A ppe (II) carbonate carbon doxide B copper (II) sulfate sulfur dioxide C iron (II) chloride chlorine D iron (II) sulfate sulfur dioxide Dilute nitric dd ed to a colourless solution P followed by aqueous barium nitrate to gi precipitate. What could P be? A copper(II) sulfate C copper(II) iodide B sodium sulfate D sodium iodide 1 cm3 of solution Q was added into two separate test tubes. To one of the test tubes, an excess of aqueous sodium hydroxide was added gradually. White precipitate which was soluble in excess aqueous sodium hydroxide was obtained. To the other test tube, an excess of aqueous ammonia was added gradually. White precipitate which was inso luble in excess aqueous ammonia was obtained. What could solution Q contain? A lead(II) chloride C calcium chloride B aluminium chloride D ammonium chloride Excess dilute nitric acid was added to compound R to give a gas and a colourless solution S. Aqueous ammonia was then added to the solution S to give white precipitate which was soluble in excess aqueous ammonia. What could compound R be? A calcium oxide C sodium hydroxide B aluminium carbonate D zinc carbonate Which of the following reagent s when added separately to dilute nitric acid and dilute sulfuric acid will be able to distinguish the two solutions? A aqueous barium nitrate C aqueous sodium nitrate B magnesium carbonate D silver chloride d co r 2 acid is a ve a white 3 4 5

2011 Secondary Three Block Test 2 Nanyang Girls’ High School Setter: A Siew Chemistry 8 Which observation is true when an alkali ne solution of potassium nitrate is warmed with aluminium powder? odourless gas is evolved. Gas relights glowing splinter.