2023 QSS Chem Prelims P1

This document consists of 18 printed pages. Name: ………………………………………………….. ( ) Class: Sec 4GR Queenstown Secondary School Preliminary Examination 2023 Secondary Four Express Chemistry 6092/01 30 August 2023 Time: 1200 – 1300h Wednesday Duration: 1 hour Setter: 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 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 the Periodic Table is printed on page 18. The use of an approved scientific calculator is expected, where appropriate.

2 Queenstown Secondary School [Turn over 1 A student wants to show that the speed of reaction between 2.00 g of zinc carbonate and 30.00 cm3 of dilute nitric acid doubles for every 5°C rise in temperature. He measures the volume of carbon dioxide produced at regular intervals. Which of the following apparatus should the student use to carry out the experiment? A burette, electronic mass balance, thermometer, gas syringe B burette, electronic mass balance, thermometer, measuring cylinder C pipette, electronic mass balance, thermometer, gas syringe D pipette, electronic mass balance, thermometer, measuring cylinder 2 The chromatogram result below shows dyes, M and N present in an ink sample. What is the Rf value of the more soluble dye? A 𝑦 𝑤+𝑥+𝑦 B 𝑦 𝑤+𝑥+𝑦+𝑧 C 𝑥+𝑦 𝑤+𝑥+𝑦 D 𝑥+𝑦 𝑤+𝑥+𝑦+𝑧 3 Which of the following tests would be able to distinguish between carbon dioxide gas and sulfur dioxide gas? 1 Insert a lighted splinter into the test-tube. 2 Place a piece of damp blue litmus paper at the mouth of the test-tube. 3 Bubble the gas into a test-tube containing limewater. 4 Bubble the gas into a test-tube containing aqueous acidified potassium manganate(VII). A 1 and 2 B 1 and 3 C 2 and 3 D 3 and 4

3 Queenstown Secondary School [Turn over 4 The flow chart below shows some reactions that blue solution W undergoes. What are the identities of W, X, Y and Z? W X Y Z A Cu(NO3)2 NaNO3 Cu(OH)2 CuSO4 B CuSO4 Na2SO4 Cu(OH)2 CuSO4 C Fe(NO3)2 NaNO3 Fe(OH)2 FeSO4 D (NH4)2SO4 NH4OH Cu(OH)2 CuSO4 5 Two experimental set-ups used to demonstrate diffusion of gases are shown in the diagram below. experiment 1 experiment 2 What changes, if any, to the water levels at P and Q would you expect to see in both experiments? experiment 1 experiment 2 A P and Q remain the same P and Q remain the same B P and Q remain the same Q is higher than P C P is higher than Q Q is higher than P D Q is higher than P Q is higher than P

4 Queenstown Secondary School [Turn over 6 A particle contains 31 protons, 40 neutrons and 28 electrons. Which symbol is correct for this particle? A 𝑁𝑖28 59 3+ B 𝑁𝑖28 59 3- C 𝐺𝑎31 71 3+ D 𝐺𝑎31 71 3- 7 X, Y and Z are 3 different elements in the Periodic Table. The ‘dot-and-cross’ diagram of the compound formed between X, Y and Z is shown below. Only the valence electrons are shown. Which statements are correct? 1 Element Y could be lithium. 2 Element X belongs to Group VII of the Periodic Table. 3 Elements X and Z are bonded together by covalent bonds. 4 There are more electrons than protons in ZX2-. A 1 and 2 only B 3 and 4 only C 1, 3 and 4 D 2, 3 and 4 8 How many electrons in total are shared between the atoms in a molecule of ethene, C2H4, and in a molecule of water, H2O? ethene water A 6 2 B 10 4 C 12 4 D 14 8

5 Queenstown Secondary School [Turn over 9 Diamond, graphite, iodine and silicon dioxide all contain covalent bonds. Which statement is correct? A Diamond has atoms that are arranged in a tetrahedral structure. B Graphite is used as a lubricant because each layer in its structure is held to the next layer by strong covalent bonds. C Iodine changes from solid to gas upon gentle warming as its covalent bonds are weak. D Silicon dioxide and graphite both can conduct electricity due to the presence of mobile electrons. 10 Which statements about metals are correct? 1 Metals are not malleable. 2 Metals conduct thermal energy. 3 Metals have a lattice of positive ions in a ‘sea of electrons’. A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and 3 11 Vanillin is the main chemical compound present in vanilla bean extract. It contains 63.16% of carbon, 5.26% of hydrogen and 31.58% of oxygen by mass. What is the empirical formula of vanillin? A C3H3O B C5H5O2 C C8H8O3 D C8H8O6 12 The airbag in a car contains sodium azide, NaN3 and potassium nitrate, KNO3. During a car accident, two reactions take place, producing nitrogen gas which allows the airbag to inflate rapidly. 2NaN3 → 2Na + 3N2 10Na + 2KNO3 → K2O + 5Na2O + N2 What is the volume of nitrogen produced when 13.0 g of sodium azide decomposes in the airbag? A 0.32 dm3 B 0.48 dm3 C 7.68 dm3 D 9.60 dm3

6 Queenstown Secondary School [Turn over 13 A washing powder contains sodium hydrogencarbonate, NaHCO3 as one of its ingredients. In a titration, a solution containing 1.00 g of the washing powder was found to react completely with 7.15 cm3 of 0.100 mol/dm of dilute hydrochloric acid. NaHCO3 + HCl → NaCl + H2O + CO2 Assuming that sodium hydrogen carbonate is the only ingredient that reacts with the acid, what is the percentage by mass of sodium hydrogencarbonate in the washing powder? A 3.0% B 6.0% C 12.0% D 24.0% 14 An electrolytic circuit is set up using inert electrodes P, Q, R and S. At which of the electrodes is a Group VII element produced? A P only B P and R C Q only D Q and S 15 Three electrochemical cells are set up using zinc metal and three other unknown metals P, Q and R as electrodes. The results of the experiment are shown in the table below. metal tested voltmeter reading / V direction of electron flow P 0.200 zinc to metal P Q 0.500 metal Q to zinc R 1.100 zinc to metal R Which of the following shows the three unknown metals in increasing order of reactivity? A P, Q, R B Q, P, R C R, P, Q D R, Q, P

7 Queenstown Secondary School [Turn over 16 The energy profile diagram for both the catalysed and uncatalysed reactions in the production of ammonia is shown below. What is the activation energy for the decomposition of ammonia in the presence of a catalyst? 17 A molecule of ethyne undergoes addition of hydrogen to form ethane. Given the following information of the bond energies, calculate the enthalpy change of the reaction. bond C — H