2023 ANDSS Chem Prelims P1

This document consists of 18 printed pages. Setter: Mr Eugene Chan O ANDERSON SECONDARY SCHOOL Preliminary Examination 2023 Secondary Four Express CANDIDATE NAME: CLASS: / INDEX NUMBER: CHEMISTRY Paper 1 6092/01 22 August 2023 1 hour 0800 – 0900 h Additional Materials : Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class and index number on the Question Paper and 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 Periodic Table is printed on page 18. The use of an approved scientific calculator is expected, where appropriate. _______________________________________________________________________________

Prelim 4E CHEM 2023 6092/1 2 1 A student wants to investigate if dissolving 2.35 g of a salt in 25.0 cm3 of water is an endothermic process. Which pieces of apparatus are required? electronic balance measuring cylinder stopwatch thermometer A     B     C     D     2 Chromatogram 1 shows the separation of coloured inks in mixture Q, using solvent A. Chromatogram 2 shows the separation using the same piece of paper in another solvent B after it has been rotated 90° anti-clockwise. How many different types of ink are present in mixture Q? A 3 B 4 C 6 D 7 rotate 90° anti-clockwise chromatogram 1 chromatogram 2 Q Q first starting line second starting line

Prelim 4E CHEM 2023 6092/1 3 3 A solution contains barium ions and sodium ions and one type of anion. What could the anion be? A chloride only B nitrate only C sulfate only D chloride or nitrate 4 The cooling curve of an impure sample of substance Y is shown. Which row gives possible melting and boiling points of a pure sample of Y? melting point / C boiling point / C A –25 125 B –30 150 C –40 140 D –55 155 temperature / °C time / min

Prelim 4E CHEM 2023 6092/1 4 5 A reaction in gas clouds of the Universe is as shown. H2 (g) + H2 +(g) → H(g) + H3 +(g) How many protons, neutrons and electrons does an H3+ ion contain? protons neutrons electrons A 2 1 1 B 2 1 2 C 3 0 1 D 3 0 2 6 Which pair of substances conducts electricity by mobile electrons? substance 1 substance 2 A aqueous potassium chloride copper metal B aqueous potassium chloride molten potassium chloride C graphite copper metal D graphite molten potassium chloride 7 The diagram shows the arrangement of ions in a compound. What is the formula of this compound? A M14X13 B M2X C MX6 D MX 8 Which molecule has an equal number of bonding electrons and non -bonding valence electrons? A CO2 B Cl2O C HF D NH3 metal ion M non-metal ion X

Prelim 4E CHEM 2023 6092/1 5 9 Copper is a metallic element. Which statements about copper are correct? 1 Copper is malleable because layers of ions are in fixed positions and cannot move. 2 The structure of copper consists of positive ions in a lattice. 3 Electrons hold copper ions together in a lattice by electrostatic attraction. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only 10 Sodium dichromate( VI), Na2Cr2O7, reacts with acid and hydrogen peroxide, H2O2, producing Cr3+ ions, water and oxygen. What is the correctly balanced ionic equation for this reaction? A Cr2O7 2ି + 2H+ + H2O2 → 2Cr3+ + 2H2O + 4O2 B Cr2O7 2ି + 8H+ + 3H2O2 → 2Cr3+ + 7H2O + 3O2 C Cr2O7 2ି + 8H+ + 6H2O2 → 2Cr3+ + 10H2O + 6O2 D Cr2O7 2ି + 14H+ + 3H2O2 → 2Cr3+ + 7H2O + 3O2 11 The relative molecular mass, Mr, of liquid Z is 60. Z contains 40.0% carbon, 6. 7% hydrogen and 53.3% oxygen. Which row shows the correct empirical and molecular formulae of Z? empirical formula molecular formula A CH2O CH2O B CH2O C2H4O2 C C2H4O2 C2H4O2 D C3H8O C3H8O

Prelim 4E CHEM 2023 6092/1 6 12 Hydrogen bromide decomposes to form hydrogen and bromine. The equation is shown. 2HBr(g) → H2(g) + Br2(g) The bond energies are shown in the table. bond bond energy in kJ/mol Br−Br 193 H−Br 366 H−H 436 What is the energy change for the reaction? A +263 kJ/mol B +103 kJ/mol C −103 kJ/mol D −263 kJ/mol 13 The table gives some information about four redox reactions. Which row gives correct information about what is oxidised and the evidence that this is oxidation? equation what is oxidised evidence for this oxidation A CuO(s) + C(s) → CO(g) + Cu(s) copper copper oxide has given oxygen to carbon B 2Na(s) + Cl2(g) → 2NaCl(s) sodium sodium has lost an electron C N2(g) + 3H2 ⇌ 2NH3(g) nitrogen nitrogen has gained hydrogen D ZnCl2(aq) + Mg(s) → MgCl2(aq) + Zn(s) zinc zinc has gained two electrons 14 Molten sodium chloride and concentrated aqueous sodium chloride are electrolysed using platinum electrodes. What are the products at the negative electrode in each electrolysis? molten sodium chloride concentrated aqueous sodium chloride A hydrogen hydrogen B hydrogen sodium C sodium hydrogen D sodium sodium

Prelim 4E CHEM 2023 6092/1 7 15 Four cells were set up using aqueous sodium chloride as the electrolyte. In each cell, only the underlined electrode dissolved. To establish the order of reactivity of the metals, it is necessary to set up two or more cells. Which pairs of cells are needed in addition to the four cells above? first cell electrodes second cell electrodes A copper / tin magnesium / zinc B iron / iron iron / zinc C magnesium / tin copper / zinc D tin / zinc magnesium / copper iron tin iron magnesium iron zinc iron copper

Prelim 4E CHEM 2023 6092/1 8 16 A large excess of magnesium ribbon is added to dilute hydrochloric acid and the volume of hydrogen gas produced is measured as the reaction proceeds. The reaction is exothermic. The results are shown. Which row explains the changes in the rate of reaction between points P and Q and between points Q and R? between points P and Q between points Q and R A the reaction temperature is increasing the acid concentration is falling B the reaction temperature is increasing the magnesium has been used up C surface area of magnesium is decreasing the acid concentration is falling D surface area of magnesium is decreasing the magnesium has been used up 17 The oxides of three elements, T, U and V, are added to water. oxide of T oxide of U oxide of V water added dissolved to form a solution of pH 10 insoluble dissolved to form a solution of pH 2 The oxide of U is white in colour. What are elements, T, U and V? T U V A calcium aluminium sulfur B calcium copper sulfur C sulfur aluminium calcium D sulfur copper calcium total volume / cm3 time / s P Q R

Prelim 4E CHEM 2023 6092/1 9 18 Dilute sulfuric acid was added to aqueous barium hydroxide until the acid was present in excess. How will the total number of ions present in the reacting mixture vary? A B amount of acid added amount of acid added C D amount of acid added amount of acid added 19 A mixture contains copper(II) carbonate and iron(II) carbonate. A sample of the mixture is dissolved in nitric acid to pro