2022 CVSS Chem Prelims P1

康 柏 中 学 COMPASSVALE SECONDARY SCHOOL PRELIMINARY EXAMINATION 2022 CHEMISTRY 6092/01 Paper 1 Multiple Choice Secondary Four Express Name: ________________________ Duration: 1 h Index No: ________ Date: 31 August 2022 Class: _________ Marks: _______ /40 READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, index number and class on the Answer Sheet in the spaces provided. There are forty questions on 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 separate Answer Sheet. Read the instructions on the Answer Sheet very carefully. 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 printed on page 15. The use of an approved scientific calculator is expected, where appropriate. ____________________________________________________________________________________ This question paper consists of 15 printed pages including this page. Setter: Miss Zhuang ���

2 1 The concentration of aqueous sodium carbonate can be found through an experiment involving a reaction with nitric acid of known concentration. Which apparatus are needed for the experiment? A burette, measuring cylinder, gas syringe B burette, pipette, conical flask C burette, pipette, stopwatch D electronic balance, measuring cylinder, gas syringe 2 Gas Y is a water-soluble, acidic gas which is less dense than air. Which method is used to collect a dry sample of gas Y? A B C D Y dry Y water dry Y calcium oxide Y dry Y Y calcium oxide concentrated sulfuric acid dry Y Y ���

3 3 Ethylamine, CH3CH2NH2 (Mr = 45), reacts with hydrogen chloride gas, HCl (Mr = 36.5) to form a white solid, ethylammonium chloride. In an experiment, the following apparatus is set up. Where will the white solid form? A B C D 4 Which statement about kinetic particle theory is correct? A Energy is taken in when a liquid changes into solid state. B Iodine particles are further apart in vapour state than in solid state. C Particles have stronger attractive forces in gaseous state than in liquid state. D When water boils, its particles lose kinetic energy. 5 When two elements react together, a compound is formed. Which statement is correct? A Equal masses of the elements must be used. B The compound formed can be easily separated into its elements. C The compound formed will have a fixed melting point. D The compound shows similar chemical properties to its constituent elements. cotton wool soaked with concentrated CH3CH2NH2 solution cotton wool soaked with concentrated HCl ���

4 6 A solution of fertiliser was tested as shown. Which ions are present in this fertiliser? A Fe2+ and NH4+ B Fe2+ and NO3– C Fe2+ and SO42– D NH4+ and NO3– 7 Which particle has the same number of neutrons and electrons? A F919– B Na1123+ C P1531 D S16322– 8 Unnilpentium is an artificial element. One of its isotopes is Unp105262. Which statement is correct? A Unp105262 has a nucleon number of 105. B Isotopes of unnilpentium have different chemical properties. C The atom Y106262 is an isotope of Unp105262. D The atom X105260 is an isotope of Unp105262. green precipitate fertiliser solution green precipitate forms warm the mixture moist red litmus paper turns blue add excess aqueous sodium hydroxide ���

5 9 Ammonium nitrate, NH4NO3, is a white crystalline salt that is commonly used in agriculture as a high-nitrogen fertilizer. Three statements about ammonium nitrate are given. statement 1 Forces of attraction between oppositely charged ions is present in ammonium nitrate. statement 2 Molten ammonium nitrate can conduct electricity as there are delocalised electrons. statement 3 There is covalent bonding in ammonium nitrate. Which statements are correct? A 1 only B 2 and 3 only C 2 only D 1 and 3 only 10 Which molecule has only six electrons used for bonding? A C2H4 B C2H6 C H2O D PCl3 11 Elements P and Q form an ionic compound P2Q. In which group of the Periodic Table is P found and how is the bond between P and Q formed? group in which P is found how the bond between P and Q is formed A I Q atom gains two electrons from two P atoms B II Q atom gains two electrons from one P atom C VI P and Q shares two electrons D VI P atom gains two electrons from two Q atoms 12 The formula of china clay (aluminium silicate) was shown in an old book as Al2O3.2SiO2.2H2O. It is shown in a modern book as Al2(OH)xSi2Oy. What are the values of x and y? x y A 2 4 B 2 5 C 4 3 D 4 5 ���

6 13 One mole of each of the following compounds is burnt in excess oxygen. Which compound would produce four moles of carbon dioxide and four moles of steam only? A C4H10 B C4H9OH C C2H5CO2H D CH3CH2CO2CH3 14 Which polymer has an empirical formula that is different from the rest? A B C D 15 A washing powder contains sodium hydrogencarbonate, NaHCO3 (Mr =84). In a titration, a solution containing 1.00 g of washing powder requires 7.15 cm3 of 0.1 mol/dm3 sulfuric acid for complete reaction. 2NaHCO3 + H2SO4 → Na2SO4 + 2CO2 + 2H2O Given that sodium hydrogencarbonate is the only ingredient that reacts with the acid, what is the percentage purity of sodium hydrogencarbonate in the washing powder? A 3.0% B 6.0% C 12.0% D 24.0% 16 The pH of an aqueous solution of hydrochloric acid is 3. What will be the pH of the solution after adding 15 g of sodium chloride? A 2 B 3 C 7 D 9 ���

7 17 Hydrazine, N2H4, is used as a rocket fuel since it reacts with oxygen to form gases that are environmentally friendly. N2H4(l) + O2(g) → N2(g) + 2H2O(g) ∆H = –534 kJ/mol Despite its use as a rocket fuel, hydrazine does not burn readily in oxygen. Which statement explains why hydrazine does not burn readily? A Hydrazine is a liquid. B The activation energy is too high. C The N≡N bond is very strong. D The reaction is exothermic. 18 W and X reacts to form Y and Z in a reversible reaction. W + X ⇌ Y + Z The energy profile diagram for this reaction is shown. Which statements are correct? 1 The enthalpy change for the backward reaction is +20 kJ/mol. 2 The forward reaction is endothermic. 3 The activation energy for the forward reaction is +70kJ/mol. A 1 and 2 B 1 and 3 C 1, 2 and 3 D 2 and 3 energy/ kJ/mol progress of reaction W + X Y + Z 50 20 ���

8 19 An alloy reacts with dilute nitric acid to evolve a gas which extinguishes a lighted splint with a ‘pop’ sound. A red-brown solid residue remains, which turns into a black solid when heated in air. Which two metals are present in this alloy? A iron and copper B iron and aluminium C silver and zinc D silver and copper 20 The diagram compares the amount of carbon in two steels, P and Q. Which row correctly compares the strength and brittleness of P and Q? strength brittleness A Q > P Q > P B Q > P P > Q C P > Q Q > P D P > Q P > Q 21 Aluminum, caesium and zinc are three commonly used metals. Caesium, Cs, is a metal that is above aluminum in the reactivity series. Which row correctly shows the extraction of the three metals? aluminium zinc caesium A electrolysing AlCl3(aq) heating ZnO with coke electrolysing CsCl(aq) B electrolysing AlCl3(aq) electrolysing ZnCl2(aq) electrolysing CsCl(l) C electrolysing Al2O3(l) heating ZnO with coke electrolysing CsCl(l) D heat