NYGH 2010-S3EOY-Chem P1

Class Register Number Name 南洋女子中学校 NANYANG GIRLS’ HIGH SCHOOL End-of-Year Examination 2010 Secondary Three CHEMISTRY 45 minutes Paper 1 Multiple Choice Friday 15 October 2010 0800 - 0845 Additional materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Do not open this booklet until you are told to do so. Write your name, class and register number on the optical answer sheet provided. There are 30 questions in this paper. Answer all questions. For each question there are four possible answers, A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the optical answer sheet. INFORMATION FOR CANDIDATES Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. A copy of the Periodic Table is given on page 8. You are allowed to use an approved scientific calculator. Setter: CHG This document consists of 8 printed pages. NANYANG GIRLS' HIGH SCHOOL [ Turn over

End of Year Examination 2010 2 Nanyang Girls’ High School Secondary Three 1 At which temperature does a conc entrated aqueous solution of sodium chloride begin to boil? A 96oC C 100oC B 99oC D 104oC 2 Valeric acid is an organic liquid that is used as an industrial reactant to synthesize esters for use in perfume s and cosmetics. It does not mix with water. Which of the following apparat us below can be used to separate a mixture of valeric acid and water? A C B D 3 An element J forms a positive ion with an octet electronic configuration. The proton (atomic) number of J is most likely ______. A 16 C 18 B 17 D 19 4 Why do ionic compounds have high melting points? A Their ions are held in fixed positi ons in a crystal lattice and cannot move freely. B Their forces between the ions are very strong and need to be overcome by a large amount of energy. C The intermolecular forces between the ions are very strong and need to be overcome by a large amount of energy. D Ionic compounds behave like metals and thus have high melting points like most metals. 5 Hydrazine, used as a rocket pr opellant, has the formula N 2H4. What is the number of hydrogen atoms in 640 g of hydrazine? A 1.20 x 1023 C 1.25 x 1025 B 6.00 x 1023 D 4.80 x 1025 Setter: CHG Chemistry / I

End of Year Examination 2010 3 Nanyang Girls’ High School Secondary Three 6 A compound Y contains 50% sulphur and 50% oxygen by mass. What is the empirical formula of compound Y? A SO C SO3 B SO2 D SO4 7 Which of the following contains the lowest concentration of hydrogen ions? A 2 mol/dm3 H2SO4 C 2 mol/dm3 CH3COOH B 2 mol/dm3 HCl D 2 mol/dm3 HNO3 8 The table gives information about three indicators. Indicator colour at pH 1 pH at which colour changes colour at pH 12 screened methyl orange violet 3.5 green bromocresol green yellow 4.6 blue thymolphthalein colourless 9.9 blue Which colours would be obtained when each indicator was added separately to a colourless liquid of pH 6? screened methyl orange bromocresol green thymolphthalein A violet yellow colourless B green blue colourless C green blue blue D green yellow blue 9 Which of the follo wing quantities is not equivalent to 1 mole of hydrogen gas at r.t.p.? A 1.2 × 10 23 hydrogen atoms C 24 dm3 of hydrogen gas B 6 × 1023 hydrogen molecules D 2 g of hydrogen gas 10 In an experiment, 4.0 cm 3 of 1.0 mol/dm 3 aqueous copper(II) sulfate was mixed with 8.0 cm3 of 1.0 mol/dm3 aqueous sodium carbonate. CuSO4 + Na2CO3 → Na2SO4 + CuCO3 What did the reaction vessel contain when the reaction was complete? A A colourless solution only. B A green precipitate and a blue solution. C A green precipitate and a colourless solution. D A white precipitate and a blue solution. Setter: CHG Chemistry / I [Turn over

End of Year Examination 2010 4 Nanyang Girls’ High School Secondary Three 11 Sodium azide, NaN3, is used in car ‘air bags’. On heating the compound to 300oC, it rapidly decomposes according to the equation: 2NaN 3(s) → 2Na(s) + 3N2(g) What volume of gas, measured at r oom temperature and pressure, will be produced by the decomposition of 4 moles of sodium azide? A 64 dm 3 C 144 dm3 B 96 dm3 D 288 dm3 12 Neuroscientists believe that the chemical in chocolate that may have a feel- good effect on the human brain is phenylethylamine (PEA), C 8H11N. PEA can be made in the laboratory by the following reaction: C H 5NO2 + C8H8O → C8H11N + CO2 + H2O (PEA) What is the maximum mass of PEA t hat can be produced starting with 50 g of CH 5NO2 and 100 g of C8H8O? A 50 g C 96 g B 75 g D 101 g 13 Solid carbon dioxide (dry ice) is us ed as a refrigerating agent because it changes directly from the so lid into a gas at a low te mperature. What is the main intermolecular bonding in solid carbon dioxide? A ionic bonding C dative bonding B covalent bonding D van der Waals’ forces 14 Ammonia boils at −33 oC, whereas water boils at 100 oC. Which of the following statements best explains this difference in the boiling points? A Water has a higher molar mass than ammonia. B Water has fewer atoms per molecule than ammonia. C Each water molecule contains more electrons than ammonia. D Stronger intermolecular forces exist in water relative to ammonia. 15 Atoms of elements G and H have 16 and 19 protons respectively. G and H combine to form a compound. Which of the following is/are correct? (1) The formula of the compound is GH. (2) The compound is an ionic compound. (3) The electron arrangements of G and H in the compound are the same. A (1) only C (2) and (3) only B (2) only D (1) and (2) only Setter: CHG Chemistry / I

End of Year Examination 2010 5 Nanyang Girls’ High School Secondary Three 16 Which quantity of nickel has the smallest mass? A 6 X 1022 atoms C 17.6 g B 0.5 mol D 3.01 X 1023 Ni2+ ions 17 What is the concentration of hydrogen ions, in g/dm 3, in 0.05 mol/dm 3 sulfuric acid? A 0.05 g/dm3 C 0.20 g/dm3 B 0.10 g/dm3 D 2.00 g/dm3 18 A volume of ethane, C 2H6 at r.t.p has a mass of 20 g. What is the mass of an equal volume of propene, C3H6, at r.t.p.? A 20 g C 28 g B 21 g D 42 g 19 20 cm 3 of carbon monoxide are reacted with 10 cm 3 of oxygen. The equation for the reaction is shown. 2CO + O2 → 2CO2 Which volume of carbon dioxide will be produced? (all volumes are measure at r.t.p.) A 10 cm3 C 30 cm3 B 20 cm3 D 40 cm3 20 Which of the following is used in the chemical test for hydrogen gas? A burning splint C potassium manganate(VII) B glowing splint D red litmus paper 21 The number of valence electrons of atoms A and B are shown in the diagram. What is the most likely formula of the compound formed between A and B? A AB2 C A2B B AB4 D A2B3 BA Setter: CHG Chemistry / I [Turn over

End of Year Examination 2010 6 Nanyang Girls’ High School Secondary Three 22 25.0 cm3 of 0.100 mol/dm3 dilute sulfuric acid was placed in a conical flask. Which of the following aqueous sodium hydroxide solutions would exactly neutralize the sulfuric acid in the flask? A 25.0 cm3 of 0.050 mol/dm3 C 50.0 cm3 of 0.050 mol/dm3 B 25.0 cm3 of 0.100 mol/dm3 D 50.0 cm3 of 0.100 mol/dm3 23 When aqueous sodium hydroxide is added dropwise until in excess to an unknown salt solution,