GYSS 2024 4E Chemistry Prelims Paper 1 QP Final

2 1 The diagram shows the apparatus used to obtain a gas sample from a mixture of ammonia, hydrogen chloride, sulfur dioxide and nitrogen. Which of the following gas(es) would be present in the gas sample? A hydrogen chloride and sulfur dioxide only B sulfur dioxide and nitrogen only C ammonia only D nitrogen only 2 Two students performed paper chromatography to identify the dyes present in a food colouring sample. The two chromatograms, P and Q, are shown. What is a possible explanation for the difference in the two chromatograms? A A more concentrated sample was used in chromatogram P. B Impurities are present in the sample used for chromatogram Q. C The experiment was performed for a shorter period of time for chromatogram Q. D The solvents used for chromatogram P and Q are different. acidified potassium manganate(VII) concentrated sulfuric acid water gas sample P Q solvent front start line

3 3 The information of two substances, E and F are given. Four substances, which could be E and F, are given below. Which row shows substances E and F? substance E F arrangement of particles disorderly and randomly close and not orderly movement of particles moving in all directions at high speed sliding around randomly substance description 1 water at 150 ºC 2 magnesium at 200 ºC 3 ethanol at 40 ºC 4 potassium oxide at 10 ºC E F A 1 2 B 1 3 C 2 1 D 4 3 4 The following apparatus is set up, using different gases in the two inverted beakers. Which pair of gases would cause an upward movement of the water level at X? gas 1 gas 2 A chlorine fluorine B chlorine hydrogen C helium fluorine D helium hydrogen X porous pot air gas 1 water air porous pot gas 2 beaker

4 5 The nucleon number and number of electrons of elements M and N are shown. Which statement about M and N is correct? element nucleon number number of electrons M 15 7 N 24 12 A An atom of M has more neutrons than an atom of N. B M and N will combine to form a compound with a molecular mass of 102. C M is a stronger reducing agent than N. D N is in the same period in the Periodic Table as M. 6 Zircaloy-4 is an alloy comprising 98.0% zirconium, 1.5% tin and 0.5% iron. It is often used to make the parts of nuclear power plants and aircrafts. Which of the following statements is true about zircaloy-4? A It is resistant to corrosion as the zirconium and tin atoms form a protective layer over the iron. B It is strong as the tin and iron atoms form strong bonds with the zirconium atoms. C It conducts electricity as the metal cations can act as mobile charge carriers when a potential difference is applied. D It is hard as the atoms have different sizes and cannot slide over each other easily. 7 The table shows the physical properties of substances P, Q, R and S. Using the information in the table, which statement about P, Q, R and S is incorrect? substance melting point / ºC electrical conductivity in solid state in molten state P 2300 poor poor Q 800 poor good R 80 poor poor S 1200 good good A Substance R consists of weak bonds between the atoms. B Substance Q consists of strong electrostatic attraction between oppositely charged particles. C Substance P and S are both insoluble in water. D Substance S consists of a ‘sea of delocalised electrons’.

5 8 Graphane has a similar structure to graphite except that it has one hydrogen atom attached to each carbon atom as shown. The following statements are used to describe graphane. 1 It has a giant molecular structure. 2 It conducts electricity in the solid state. 3 It is soft. Which statements are correct? A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and 3 9 Oxygen gas can be converted into ozone by passing it through an electric discharge. 3O2 (g) ⇌ 2O3 (g) In an experiment, 600 cm3 of oxygen gas was used but only 20% was converted into ozone. What is the total volume of gases present at the end of the experiment? A 400 cm3 B 520 cm3 C 560 cm3 D 600 cm3 10 Cynogen is a compound used as a rocket propellant. 0.845 g of cynogen occupied 390 cm3 at room temperature and pressure. What is the molecular formula of cynogen? A CH3NO B C2H3N C C2N2 D HCN hydrogen atom carbon atom

6 11 Reactions 1, 2 and 3 are used in the manufacture of three fertilisers, namely (NH4)2SO4, Ca(H2PO4)2, and (NH4)3PO4. Reaction 1: H2SO4 + 2NH3 → (NH4)2SO4 Reaction 2: 2H2SO4 + Ca3(PO4)2 → Ca(H2PO4)2 + 2CaSO4 Reaction 3: 3H2SO4 + Ca3(PO4)2 + 6NH3 → 2(NH4)3PO4 + 3CaSO4 The relative molecular mass, Mr, of sulfuric acid and of each fertiliser is shown in the table. In each reaction, 196 g of sulfuric acid was used. Which reaction will produce the least and greatest mass of fertiliser? substance H2SO4 (NH4)2SO4 (NH4)3PO4 Ca(H2PO4)2 Mr 98 132 149 234 least mass greatest mass A 1 3 B 2 3 C 2 1 D 3 1 12 In an experiment, excess calcium carbonate was reacted with dilute hydrochloric acid. It was observed that the reaction gradually became slower and eventually stopped. Which statement best explains the observations? A Calcium carbonate was used up completely. B There were no more hydrogen ions in the reaction mixture. C An insoluble layer of calcium chloride is formed around calcium carbonate. D Carbon dioxide produced reacts with calcium carbonate to give a white precipitate.

7 13 When dilute sulfuric acid and potassium hydroxide react, a two-step reaction occurs. Step 1: Potassium hydrogen sulfate, KHSO4 is formed. H2SO4 (aq) + KOH (aq) → KHSO4 (aq) + H2O (l) Step 2: Aqueous potassium hydrogen sulfate reacts with more potassium hydroxide to form potassium sulfate. KHSO4 (aq) + KOH (aq) → K2SO4 (aq) + H2O (l) Which results for these two salts, when tested with blue litmus paper, are correct? salt effect on blue litmus paper A KHSO4 K2SO4 turns red no effect B KHSO4 K2SO4 turns red turns red C KHSO4 K2SO4 no effect turns red D KHSO4 K2SO4 no effect no effect 14 A student is given six reagents as shown to make salts. dilute nitric acid dilute hydrochloric acid dilute sulfuric acid solid copper(II) carbonate solid lead(II) oxide solid silver hydroxide How many soluble salts can be prepared from these reagents? A 4 B 5 C 6 D 7

8 15 An aqueous solution contains the same amount of Ca2+ and Cu2+ ions. Aqueous ammonia is added until in excess. After shaking, the mixture is filtered. What would be left on the filter paper? A no solid residue B blue solid C blue solid and white solid D white solid 16 When solid Z was added to dilute sulfuric acid, effervescence was observed and a colourless solution was obtained. When solid Z was added to an aqueous mixture of sodium hydroxide and sodium nitrate and warmed, a gas was evolved which turned moist red litmus paper blue. What could Z be? A aluminium B ammonium nitrate C copper nitrate D zinc carbonate 17 Industrial ammonia is obtained by the Haber Process. N2 (g) + 3H2 (g) ⇌ 2NH3 (g) ∆H = –92 kJ/mol Which of the following statements about the Haber Process is incorrect? A Hydrogen gas needed for the process is obtained mainly by cracking of large hydrocarbons. B Energy is released from the Haber Process. C The catalyst increases the rate of the forward reaction only and favours the production of ammonia. D The industrial catalyst used is finely-divided iron. 18 In which reaction is substance