NYGH 2013-S3BT1-Chem

Class Register Number Name 南洋女子中学校 NANYANG GIRLS' HIGH SCHOOL BLOCK TEST 1 Secondary Three CHEMISTRY 1 hour Monday 08 April 2013 1115-1215 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 11. Topics to be tested: Acids and Bases Salt preparation Ionic equations Qualitative analysis Examiner’s Use Section A (15 marks) Section B (20 marks) Section C (10 marks) Total (45 marks) Setter: CHG This document consists of 11 printed pages. NANYANG GIRLS' HIGH SCHOOL [ Turn over]

2013 Block Test 1 Nanyang Girls’ High School Secondary Three Setter: CHG. Chemistry 2 Section A (15 Marks) Answer the questions (1-15) by filling the answer in the table below. 1 6 11 2 7 12 3 8 13 4 9 14 5 10 15 Section B (20 marks) Answer all questions in this section in the spaces provided B1 State the formulae of compounds E to G. (a) Aqueous sodium hydroxide was added dropwise to an aqueous solution of E. A white precipitate which was insoluble in excess aqueous sodium hydroxide was observed. When a mixture of aqueous silver nitrate and dilute nitric acid was added to another sample of an aqueous solution of E, a white precipitate was formed. [2] E: (b) When aqueous sodium hydroxide was added to an aqueous solution of F, a pungent gas was evolved upon warming the mixture which turned moist red litmus blue. When dilute hydrochloric acid was added to another sample of an aqueous solution of F, a colourless and odourless gas, which formed a white precipitate in limewater, was evolved. [2] F: (c) Aqueous ammonia was added dropwise to an aqueous solution of G. A blue precipitate which was soluble in excess aqueous ammonia was observed. When a mixture of aqueous lead(II) nitrate and dilute nitric acid was added to another sample of an aqueous solution of G, a yellow precipitate was formed. [2] G:

2013 Block Test 1 Nanyang Girls’ High School Secondary Three 3 (c) Aqueous ammonia was added dropwise to an aqueous solution of H. A white precipitate which was soluble in excess aqueous ammonia was observed. When aqueous sodium hydroxide and a piece of aluminium foil were added to another sample of an aqueous solution of H, a gas was evolved upon warming the mixture which turned moist red litmus blue. [2] H: B2 (a) Sulfuric acid is a dibasic acid. (i) Define the term “dibasic”. [1] (ii) State the formulae of the two possible salts formed when dilute sulfuric acid reacts with aqueous sodium hydroxide. [2] (b) A student immerses a pH meter into 25.0 cm3 of an acid. He obtained a pH reading of 2.5 and concluded that the acid is strong. Comment on the validity of his conclusion. [2] (c) Describe a chemical test to distinguish between aqueous lead(II) nitrate and aqueous aluminium nitrate and state the expected observations. [3]

2013 Block Test 1 Nanyang Girls’ High School Secondary Three Setter: CHG. Chemistry 4 B3 P, Q and R are elements of the Periodic Table that belong to the same period. The table below shows the formulae of the oxide compounds of these elements. Element Mass Number of Element Formula of oxide P 24 PO Q 27 Q2O3 R 32 RO2 (a) Which of the above elements form oxides that react with akalis? [1] (b) Which of the above elements form oxides that are soluble in water? [1] (c) Write the ionic equation for the reaction between the oxide of P and hydrochloric acid. [2] END OF SECTION B

2013 Block Test 1 Nanyang Girls’ High School Secondary Three 5 Section C (10 marks) Answer all questions in this section in the spaces provided C1 A student prepared a pure and dry sample of potassium nitrate crystals using the titration method. The solubility versus temperature graphs of various compounds are as shown below. Source: http://faculty.uml.edu/james_hall/84124/solubility.htm (a) State two suitable reagents that can be used to prepare a pure and dry sample of potassium nitrate. [2] (b) Write the ionic equation for the reaction between the reagents in (a). [2]

2013 Block Test 1 Nanyang Girls’ High School Secondary Three Setter: CHG. Chemistry 6 (c) Explain whether potassium metal is a suitable reagent in the preparation of potassium nitrate. [1] (d) Describe the procedure used to obtain dry potassium nitrate crystals. [3] (e) Another student wants to prepare pure sodium chloride salt. With reference to the solubility versus temperature graph above, explain why evaporation to dryness is preferred to crystallization as the final step? [2] END OF SECTION C

2013 Block Test 1 Nanyang Girls’ High School Secondary Three 7 Section A (15 marks) Choose the most suitable answer and write its letter in the answer table provided on Page 2. 1 Which of the following is not a product when ammonium carbonate reacts with potassium hydroxide? A ammonia gas B carbon dioxide gas C potassium carbonate D water 2 Which of the following does not react with acids to produce hydrogen gas? I II III IV silver gold zinc copper A I and II only C I, II and IV only B III and IV only D All of the above 3 When two aqueous solutions, R and S, were added together, a colourless solution was obtained. What could R and S be? R S A CaCl2 NaOH B KCl Fe(NO3)3 C CuSO4 NaCl D NH4NO3 KOH 4 Which of the following reagents could be used to distinguish between aqueous ammonium sulfate and aqueous zinc sulfate? A dilute hydrochloric acid B dilute aqueous sodium hydroxide C aqueous barium chloride D aqueous silver nitrate 5 A reddish-brown precipitate was formed after aqueous ammonia was added to aqueous iron(II) chloride and the mixture was left to stand. What is the chemical formula of the precipitate? A Fe2O3 C Fe(OH)2 B FeO D Fe(OH)3

2013 Block Test 1 Nanyang Girls’ High School Secondary Three Setter: CHG. Chemistry 8 6 Excess aqueous ammonia is added to aqueous solutions of the following ions and the mixture is filtered. In which case will the result be a coloured filtrate and no residue left on the filter paper? A Al3+ C Fe2+ B Cu2+ D Fe3+ 7 The ionic equation for the reaction between zinc sulfate and sodium hydroxide is : A 2Na+ (aq) + SO4 2− (aq)  Na2SO4 (aq) B 2Zn+ (aq) + 2OH− (aq)  ZnOH (s) C Zn2+ (aq) + 2OH− (aq)  Zn(OH)2 (aq) D Zn2+ (aq) + 2OH− (aq)  Zn(OH)2 (s) 8 The ionic equation for the neutralization reaction between aqueous ammonia and dilute hydrochloric aci