GESS 3EXP CHEM EYE P2 2023 ANS

8 GESS 3EXP CHEM P2 EYE 2023 TKG A7 The following reaction scheme describes some of the reaction carried out on an unknown mixture. This mixture contains three different salts. (a) Identify the following substances. P: …………………………………………………………………………………. Q: …………………………………………………………………………………. R: …………………………………………………………………………………. S: …………………………………………………………………………………. T: …………………………………………………………………………………. U: …………………………………………………………………………………. [6] (b) Suggest two of the salts that the mixture contains. salt 1: …………………………………………………………………………….. salt 2: …………………………………………………………………………….. [2] [Total: 8]

10 GESS 3EXP CHEM P2 EYE 2023 TKG A9 Wollastonite, CaSiO3, can be produced from the reaction between calcium phosphate and silicon dioxide. 2Ca3(PO4)2 + 6SiO2 → P4O10 + 6CaSiO3 100 g of calcium phosphate, Ca3(PO4)2, was used in this reaction. The actual mass of wollastonite produced was 87 g. Calculate the percentage yield of wollastonite. [4] [Total: 4]

17 GESS 3EXP CHEM P2 EYE 2023 TKG B12 30.0 cm3 of 0.80 mol/dm3 nitric acid was reacted with 10 g of magnesium. (a) Calculate the mass of magnesium nitrate produced. [3] (b) A gas was produced in this reaction. Describe the test and observation to confirm the identity of the gas. …………………………………………………………………………………….. …………………………………………………………………………………….. [1] (c) Suggest a change in observation if nitric acid was replaced with ethanoic acid, CH3COOH, for this reaction. Explain why. …………………………………………………………………………………….. …………………………………………………………………………………….. …………………………………………………………………………………….. …………………………………………………………………………………….. [2]

18 GESS 3EXP CHEM P2 EYE 2023 TKG (d) Describe the steps to prepare pure and dry magnesium nitrate crystals from nitric acid and magnesium. …………………………………………………………………………………….. …………………………………………………………………………………….. …………………………………………………………………………………….. …………………………………………………………………………………….. …………………………………………………………………………………….. …………………………………………………………………………………….. …………………………………………………………………………………….. …………………………………………………………………………………….. …………………………………………………………………………………….. …………………………………………………………………………………….. …………………………………………………………………………………….. …………………………………………………………………………………….. [4] [Total: 10] END OF PAPER

GESS 3EXP CHEM P2 EYE 2023 TKG 11 34 When sulfur is burned, sulfur dioxide is produced. How can the identity of sulfur dioxide be confirmed? test observation A insert a glowing splint into the gas the glowing splint rekindles B use a piece of damp blue litmus paper blue litmus paper turns red and is then bleached C use a piece of damp red litmus paper red litmus paper turns blue and is then bleached D use a piece of filter paper soaked with acidified potassium manganate(VII) purple potassium manganate(VII) turns colourless 35 Separate tests were performed on an unknown solution. The results are shown in the table below. test observation add aqueous sodium hydroxide green precipitate forms and is insoluble in excess sodium hydroxide add nitric acid no observable change add aqueous sodium hydroxide, aluminium foil and warm pungent gas evolved which turned moist red litmus paper blue What is the unknown solution? A ammonium nitrate B iron(II) carbonate C iron(II) nitrate D iron(III) sulfate 36 A property of the elements from carbon to aluminium is shown on the chart. What are the elements arranged according to? A group number B number of electron shells C number of protons D valency

GESS 3EXP CHEM P2 EYE 2023 TKG 12 37 Which statement is true for all noble gases? A They are coloured elements. B They are stable and inert. C They have high densities. D They have the octet configuration. 38 Halogens can take part in displacement reactions. X2 + 2NaBr  2NaX + Br2 Some halogens are listed below. I fluorine II chlorine III iodine IV astatine Which halogens could X be? A I and II B I and IV C II and III D III and IV 39 A metal carbonate was heated as shown in the diagram below. The metal carbonate was heated strongly for an hour, but the limewater showed no observable change. Which of the following could the metal carbonate most likely be? A calcium carbonate B magnesium carbonate C sodium carbonate D zinc carbonate

GESS 3EXP CHEM P2 EYE 2023 TKG 13 40 The table below shows some information on four metals and their compounds. Metal adding hydrochloric acid heating with hydrogen adding the metal to a solution of the sulfate of J G hydrogen evolved steam produced no visible change H no visible change steam produced no visible change I hydrogen evolved no visible change J formed J hydrogen evolved no visible change no visible change What is the order of reactivity of these metals? least reactive  most reactive A H I G J B I G J H C H G J I D J G H I END OF PAPER