BLSS Prelim P1

2 BLS/PRELIM/2024/4E/CHEMISTRY/6092/01 1 The graph shows the change in temperature with time when ice at –20 oC is heated to 120 oC. Which row shows the correct change taking place between the points? points change A P to Q average energy of particles remain constant B Q to R ice melting C R to S the volume of steam is increasing D T to U water boiling 2 The apparatus can be used to show the diffusion of gases. Which pair of gases X and Y would cause no movement of the coloured water? X Y A C2H4 C2H6 B C2H4 N2 C CO2 C2H6 D CO NO 2 3 Which apparatus is most suitable to measure 27.8 cm3 of a solution? A burette B beaker C pipette D measuring cylinder temperature / oC time porous pot beaker coloured water gas X

3 BLS/PRELIM/2024/4E/CHEMISTRY/6092/01 4 Which mixture can be separated into its components by adding water, stirring and filtering? A calcium carbonate and sodium chloride B magnesium and iron C sodium chloride and copper(II) sulfate D sulfuric acid and hydrochloric acid 5 Which ion has the most number of shells that contain electrons? A Al3+ B Be2+ C N3– D S2– 6 The relative atomic mass of naturally occurring chlorine is not a whole number. What is the reason for this? A Chlorine atoms can have different numbers of neutrons. B Chlorine is unstable. C Naturally occurring chlorine cannot be obtained pure. D The mass of the electrons has been included. 7 Which statement explains why potassium chloride, KCl, has a lower melting point than calcium oxide, CaO? A Potassium chloride is covalent but calcium oxide is ionic. B Potassium is more reactive than calcium. C The attraction between the potassium ions and chloride ions is weaker than that between the calcium ions and oxide ions. D The melting point of potassium is lower than that of calcium. 8 The diagram shows the structure of a compound of carbon and silicon, (SiC)n. What will be a property of (SiC)n? A acts as a lubricant B conducts electricity C insoluble in water D low melting point 9 The element R has three electrons in its outer shell. What is the formula of the oxide of element R? A RO3 B R2O3 C R2O5 D R3O2

4 BLS/PRELIM/2024/4E/CHEMISTRY/6092/01 10 Over 71 000 kg of oil-soaked sand was scooped up from the three Sentosa beaches, one day after tonnes of fuel leaked into the sea from an oil spill. The contaminated sand was sent to an industrial waste processing facility. The oily sand is fed into a thermal desorption unit and heated up to 600°C. The resulting vapour of oil and water is collected and stored separately. The treated sand is then reused as sandbags for flood control. What is the reason that the sand can withstand heating up to 600°C in the thermal desorption unit? A Sand is a mixture of different minerals that undergo chemical reactions at high temperatures. B Sand is composed mainly of silicon dioxide, which forms strong covalent bonds with a very high melting point. C Sand contains minerals that vaporise at high temperatures, leaving behind clean sand. D Sand has a crystalline structure with weak intermolecular forces that allows it to resist heat. 11 What is the ratio of the volume of 4 g of hydrogen to the volume of 32 g of methane, both volumes at r.t.p.? A 1 to 1 B 1 to 2 C 1 to 8 D 2 to 1 12 A beaker contains 15 cm3 of 0.3 mol/dm3 sulfuric acid. Which volume of 0.3 mol/dm3 sodium hydroxide must be added to exactly neutralise all the acid? A 12 cm3 B 15 cm3 C 30 cm3 D 45 cm3 13 How many moles of iron can be extracted from 116 g of Fe3O4? A 1.0 mol B 1.5 mol C 2.0 mol D 3.0 mol 14 What is the mass of water produced when 32 g of oxygen reacts with 6 g of hydrogen? A 1 g B 2 g C 18 g D 36 g

5 BLS/PRELIM/2024/4E/CHEMISTRY/6092/01 15 The following statements about dilute sulfuric acid are all correct. 1 A white precipitate is formed when aqueous barium chloride is added. 2 The solution turns anhydrous copper(II) sulfate from white to blue. 3 Addition of Universal Indicator shows that the solution has a pH value of less than 7.0. 4 The solution reacts with copper(II) oxide forming a blue solution. Which statements confirm the acidic nature of the solution? A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4 16 Which ionic equation represents the neutralisation of aqueous sodium hydroxide with dilute nitric acid? A H+ + OH –  H2O B Na+ + NO3 –  NaNO3 C Na+ + HNO3  NaNO3 + H+ D NaOH + H+  Na+ + H2O 17 A white solid is often seen around the stoppers of bottles containing sodium hydroxide solution. Which substance has reacted with sodium hydroxide to form the solid? A carbon dioxide in the air B glass C oxygen in the air D water in the solution 18 An aqueous solution of a salt, Y, is placed in a test tube and aqueous ammonia is gradually added. The height of the precipitate in the test tube is plotted against the volume of aqueous ammonia solution added. What is Y? A aluminium sulfate B copper(II) sulfate C iron(II) sulfate D lead(II) nitrate height of precipitate volume of aqueous ammonia added

6 BLS/PRELIM/2024/4E/CHEMISTRY/6092/01 19 When heated, solid W gives off a gas. When this gas is bubbled through limewater, a white precipitate is formed. The residue after heating solid W reacts with dilute acid and also with aqueous alkali. What is W? A copper(II) carbonate B magnesium carbonate C sodium carbonate D zinc carbonate 20 A student carried out the following series of tests on an aqueous solution of sodium carbonate and recorded his results in the table below. Which test should be repeated because of an incorrect observation entered in the table? test observation A add barium chloride solution white precipitate formed B add copper(II) sulfate solution blue precipitate formed C add dilute hydrochloric acid effervescence occurred D add sodium hydroxide solution white precipitate formed 21 When testing for a chloride ion using silver nitrate, the solution must be acidified with dilute nitric acid. What is the purpose of the nitric acid? A to act as a catalyst B to oxidise the chloride ion C to prevent precipitation of silver carbonate D to prevent the decomposition of any silver chloride formed 22 Which method would not produce ammonia? A heating concentrated aqueous ammonia B heating ammonium chloride with calcium hydroxide C heating ammonium sulfate with sodium hydroxide D heating ammonium sulfate with dilute hydrochloric acid 23 Nitrogen and hydrogen react in a closed vessel. N2 (g) + 3H2 (g) ⇌ 2NH3 (g) How do the speeds of the forward and reverse reactions change, if the pressure in the vessel is increased but the temperature is kept constant? speed of forward reaction speed of reverse reaction A increases increases B decreases does not change C does not change increases D decreases decreases 24 Which process does not involve either oxidation or reduction? A formation of ammonium sulfate from ammonia and sulfuric acid B formation of nitrogen monoxide from ammonia C formation of sulfuric acid from sulfur D formation of zinc from zinc blende (ZnS)

7 BLS/PRELIM/2024/4E/CHEMISTRY/6092/01 25 Acidified potassium manganate(VII) is added to solution of X. The mixture changes from pur