SST Class Test 2 Chem

Page 1 of 11 [Turn over [ Turn over 2023 SECONDARY 3 CLASS TEST 2 CHEMISTRY 18 August 2023 (Friday) 50 minutes CANDIDATE NAME CLASS INDEX NUMBER READ THESE INSTRUCTIONS FIRST Do not turn over the page until you are told to do so. Write your name, class, and index number in the spaces provided above. Write in dark blue or black pen. Do not use staples, paper clips, highlighters, glue or correction fluid/tape. 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. Choose the one you consider correct and record your choice in the table on Page 2. Sections B Answer all the questions. Write your answers in the spaces provided on the question paper. INFORMATION FOR CANDIDATES The number of marks is given in brackets [ ] at the end of each question or part question. The total mark for this paper is 40. Approved electronic calculators are allowed for use in this paper. A copy of the Periodic Table is printed on page 11. This document consists of 11 printed pages including the cover page. Section A Section B Total 40 For Examiner’s Use

Page 2 of 11 [Turn over [ Turn over Section A Write your answers clearly in the table below. Question 1 2 3 4 5 6 7 8 9 10 Answer 1 Element P has a lattice of positive ions and a ‘sea of electrons’. Which statement describes P? A It conducts electricity by the movement of ions and electrons. B It is not malleable. C It is decomposed by an electric current. D It requires a large amount of heat to change its state from solid to liquid. 2 Nitrogen crystals are obtained by freezing nitrogen at -196 oC. What will the nitrogen crystals contain? A nitrogen atoms only B nitrogen molecules only C nitrogen atoms and molecules D nitrogen ions and nitrogen atoms 3 Which diagram shows the structure of graphite?

Page 3 of 11 [Turn over [ Turn over 4 Sulfur forms compounds with the elements hydrogen, oxygen and magnesium. These compounds have the formulae X2S, YS and SZ2, where S represents sulfur. What are the identities of X, Y and Z? H O Mg A Z X Y B Y X Z C X Z Y D Z Y X 5 The Avogadro constant is the number of A atoms in 24 g of magnesium. B atoms in 28 g of helium. C chloride ions in 95 g of magnesium chloride. D molecules in 35.5 g of chlorine. 6 Silver ions react with chloride ions as shown in the ionic equation below. Ag+(aq) + Cl- (aq) ⟶ AgCl(s) It is found that 5 cm3 of a 0.1 mol/dm3 solution of the chloride of metal Q needs 10 cm3 of 0.1 mol/dm3 silver nitrate for complete reaction. What is the formula of the chloride of metal Q? A QCl4 B Q2Cl C QCl D QCl2 7 On adding 50 g of impure limestone, CaCO3 (Mr = 100), to excess hydrochloric acid, 6.0 dm3 of CO2 was evolved at room temperatu