2022 WSSS Chem Prelims P1

West Spring Secondary School Preliminary Examination 2022 CHEMISTRY Paper 1 6092/01 SECONDARY 4 EXPRESS Name ( ) Date 31 August 2022 Class Duration 1 hour Additional materials: Laminated Periodic Table, Answer Sheet READ THESE INSTRUCTIONS FIRST Write your index number, class and name on the Answer Sheet. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. 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 laminated Periodic Table is provided separately. The use of an approved scientific calculator is expected, where appropriate. This document consists of 16 printed pages including the cover page. Setter: Mdm Sharena [Turn over ���

2 1 A student follows the rate of the reaction when 0.19 g of calcium carbonate reacts with excess acid at room temperature and pressure. What is most suitable for measuring volume of gas produced at different times during this experiment? A a 50 cm3 gas syringe B an inverted 250 cm3 measuring cylinder filled with water C an inverted 50 cm3 burette filled with water D place the apparatus on a balance and measure the loss in mass 2 The apparatus shown in the diagram was set up. Which gas, when present inside the beaker, will cause the water level at X to fall? A ammonia, NH3 C hydrogen, H2 B carbon dioxide, CO2 D nitrogen, N2 beaker porous pot water X air ���

3 3 Some students are asked to describe the difference between the particles in gases and liquids. Three of their suggestions are: 1 Particles in gases are further apart than particles in liquids. 2 Particles in gases are bigger than particles in liquids. 3 Particles in gases are smaller than particles in liquids. Which suggestion or suggestions are correct? A 1 only B 2 only C 3 only D 1, 2 and 3 4 The graph shows a change of temperature when substance Y is heated. Which stage shows that substance Y is melting? A A to B B B to C C D to E D E to F 5 At which temperature does a concentrated aqueous solution of sodium chloride begin to boil? A 93 °C B 99 °C C 100 °C D 104 °C temperature / °C 80 15 time / min A B C D E F ���

4 6 Fractional distillation is used to distil ethanol (boiling point 78°C) from a dilute ethanol solution. Which graph best shows the change in concentration of ethanol in the boiling flask as distillation proceeds? A B C D thermometer fractionating column boiling flask mixture of ethanol and water heat water in water out concentration of ethanol concentration of ethanol concentration of ethanol concentration of ethanol time time time time ���

5 7 Some properties of four substances P, Q, R and S are given in the table below. substance percentage composition by mass electrical conductivity when solid effect of heat P constant yes solid burns in air to form an oxide Q varies no liquid burns to form carbon dioxide and water R constant no solid decomposes to form two products S varies yes solid melts Which classification of the substances as an element, a mixture or a compound is correct? element compound mixture A P Q, R S B P R Q, S C R Q, P S D S P Q, R 8 An ion Q3- has 18 electrons. If its nucleon number is 31, what is the composition of its nucleus? A 15 protons and 15 neutrons B 15 protons and 16 neutrons C 18 protons and 13 neutrons D 21 protons and 10 neutrons 9 Which statement about atoms is correct? A The mass of an atom is almost entirely due to its nucleus. B The nucleus and the electrons repel each other. C The protons and neutrons have opposite charges. D The shell nearest to the nucleus always contains the most electrons. ���

6 10 Graphane, an allotrope of carbon has a similar structure to graphite, except that, it has one hydrogen atom attached to each carbon as shown in the diagram. Which set of properties will graphane have? 1 It is soft. 2 It has a giant molecular structure. 3 It conducts electricity in the solid state. A 1 and 2 B 1 and 3 C 2 and 3 D 1, 2 and 3 11 Carbon disulfide is a simple covalent compound used in manufacturing polymers. Which statement about carbon disulfide would you predict to be true? A It has a low boiling point and conducts electricity when molten. B It has a low boiling point and is soluble in organic solvents. C It is a crystalline solid at room temperature and conducts electricity when molten. D It is a crystalline solid at room temperature and is soluble in organic solvents. 12 The formula of thallium carbonate is Tl2CO3 and that of sodium chlorite is NaClO2. What is the formula of thallium chlorite? A TlClO2 B Tl2ClO2 C Tl(ClO2)2 D Tl2(ClO2)3 hydrogen atom carbon atom ���

7 13 Two of the reactions used in the manufacture of nitric acid, HNO3, are shown. 2NO + O2 → 2NO2 4NO2 + 2H2O + O2 → 4HNO3 What is the maximum number of moles of nitric acid which could be formed from one mole of nitrogen monoxide, NO? A 0.5 mol B 1.0 mol C 2.0 mol D 4.0 mol 14 Basic copper carbonate, Cu2CO3(OH)2, is used as a pigment in paint. What is the percentage by mass of copper in basic copper carbonate? A 28.8 % B 31.2 % C 57.7 % D 62.4 % 15 20 cm3 of hydrogen is reacted with 20 cm3 of oxygen as shown in the equation. 2H2 (g) + O2 (g) → 2H2O (l) What are the volumes of gases remaining at the end of the reaction? [All volumes are measured at room temperature and pressure.] volume of hydrogen / cm3 volume of oxygen / cm3 volume of product / cm3 A 0 0 20 B 0 0 40 C 0 10 0 D 10 10 0 16 Which statement best explains why farmers should not lime the soil and add ammonium nitrate fertiliser at the same time? A It is too costly to add both substances together at the same time. B The lime makes the soil too alkaline for plant growth. C The lime will react with ammonium nitrate and result in the loss of nitrogen. D The lime will react with ammonium nitrate to produce acidic substances that inhibit plant growth. ���

8 17 The table gives information about three indicators. indicator colour change low pH high pH pH at which colour change takes place methyl orange red yellow 4.0 bromothymol blue yellow blue 6.5 phenolphthalein colourless pink 9.0 If equal volumes of these three indicators were mixed, which colour would be observed at pH 5? A blue B green C orange D yellow 18 How many different sulfates in total could be prepared by the reaction of dilute sulfuric acid with the following substances?  copper  magnesium  silver  zinc carbonate A 1 B 2 C 3 D 4 19 An aqueous solution of a chloride is made by the reaction of hydrochloric acid with the hydroxide of metal M: M(OH)2 (s) + 2HCl (aq) → MCl2 (aq) + 2H2O (l) Which metal cannot be M? A copper B iron C lead D magnesium ���