Oxford Cambridge and RSA GCSE (9 1) Combined Science A (Gateway Science) /09 Chemistry Foundation and Higher Tier Year 10 Test Time allowed: 1 hour 10 minutes You must have: a ruler (cm/mm) the Data Sheet You may use: a scientific calculator First name Last name Centre number Candidate number INSTRUCTIONS Use black ink. You may use an HB pencil for graphs and diagrams. Complete the boxes above with your name, centre number and candidate number. Answer all the questions. Write your answer to each question in the space provided. Additional paper may be used if required but you must clearly show your candidate number, centre number and question number(s). Do not write in the barcodes. INFORMATION The total mark for this paper is 60. The marks for each question are shown in brackets [ ]. Quality of extended response will be assessed in questions marked with an asterisk (*) This document consists of 20 pages. DC (NF/SW) 153346/1 OCR is an exempt Charity Turn over
2 SECTION A Foundation Answer all the questions. 1 A student tests a gas. The gas turns limewater cloudy. What is the name of the gas? A B C D carbon dioxide chlorine hydrogen oxygen Your answer 2 Elements in the Periodic Table are metals or non-metals. Which of the elements is a non-metal? A B C D caesium calcium magnesium phosphorus Your answer
3 3 The electron arrangement for an element is 2, 8, 6. In which group of the Periodic Table is this element found? A 2 B 3 C 6 D 8 Your answer 4 Sodium sulfate contains sodium ions, Na +, and sulfate ions, SO 4 2. What is the formula for sodium sulfate? A NaSO 4 B Na(SO 4 ) 2 C Na 2 SO 4 D Na 2 (SO 4 ) 2 Your answer Turn over
4 5 Look at this reaction profile. B C reactants energy A product D progress of reaction Which letter shows the activation energy? Your answer
5 SECTION B Foundation 6 Iodine, I 2, is a solid at room temperature and pressure. (a) Describe the motion and arrangement of iodine molecules in solid iodine.... [2] (b) When solid iodine is heated it changes directly into a gas. Describe the motion and arrangement of iodine molecules in iodine gas.... [2] (c) Iodine, I 2, reacts with hydrogen to make hydrogen iodide, HI. (i) Write the balanced symbol equation for this reaction.... [2] (ii) This reaction is a chemical change. What is meant by a chemical change?...... Turn over
7 A student investigates the electrolysis of copper sulfate solution using inert electrodes. Look at the apparatus that she uses. dc supply + 6 cathode anode copper sulfate solution (a) Copper sulfate solution contains these particles. Cu 2+ H 2 O OH H + SO 4 2 Which two particles are attracted to the cathode?... and... (b) What is meant by an inert electrode?...
(c) The student does the electrolysis five times. She does the experiment for 2, 4, 6, 8 and 10 minutes She measures the mass of copper made each time. Look at the graph of her results. 0.5 0.4 7 mass of copper (g) 0.3 0.2 0.1 0 0 2 4 6 time (minutes) 8 10 (i) (ii) Draw a line of best fit. Use your line of best fit to calculate the rate that copper is made in grams per minute. answer:... g/mins [2] Turn over
8 A student investigates the law of conservation of mass. Look at the apparatus he uses. 8 magnesium sulfate solution thread barium chloride solution thread magnesium chloride solution and solid barium sulfate before mixing after mixing He records the total mass of the flask, test tube and contents before mixing. This mass is 124.51 g. The student tips the flask to let the two solutions mix. He then records the total mass of the flask, test tube and its contents again. (a) A reaction happens when the solutions are mixed. Look at the equation for the reaction. BaCl 2 (aq) + MgSO 4 (aq) MgCl 2 (aq) + BaSO 4 (s) (i) Write the word equation for this reaction....... (ii) What is the meaning of (aq) in the formula BaCl 2 (aq)?... (b) Predict the total mass of the flask, test tube and its contents after mixing. mass =... g
(c) Complete the table of relative formula masses. Use the space under the table for your working out. 9 Substance Relative formula mass BaCl 2 208.3 MgSO 4 MgCl 2 BaSO 4 233.4 (d) Use the relative formula masses and the symbol equation to show if mass is conserved during this reaction. [2] [2] Turn over
10 9* Tracy is separating a mixture of three substances A, B and C. Look at the table. It gives information about these substances. Substance Melting point ( C) Boiling point ( C) Solubility in water A 0 100 soluble B 114 78.5 soluble C 110 decomposes (breaks down) insoluble Suggest how Tracy can separate the mixture to get pure samples of substances A, B and C. Explain in detail how each method works.. [6]
11 SECTION C Higher 10 Graphite is an allotrope of the element carbon. It is made up of layers of carbon atoms. What type of bonds are present in the layers of carbon atoms in graphite? A B C D covalent ionic intermolecular metallic Your answer 11 Which statement best describes the structure of an atom? A B C D A nucleus containing protons and electrons, surrounded by neutrons. A nucleus containing neutrons and electrons, surrounded by protons. A nucleus containing protons and neutrons, surrounded by electrons. A nucleus containing neutrons, surrounded by electrons and protons. Your answer Turn over
12 12 The formula of ammonium sulfate is (NH 4 ) 2 SO 4. What is the relative formula mass, M r, of ammonium sulfate? A 63.1 B 114.1 C 132.1 D 216.1 Your answer 13 Lead nitrate solution, Pb(NO 3 ) 2 (aq), reacts with sodium iodide solution, NaI (aq), to form a precipitate of lead iodide. Which equation is the correct balanced ionic equation for this reaction? A Pb 2+ (aq) + I 2 (aq) PbI(s) B Pb 2+ (aq) + 2I (aq) PbI 2 (s) C Pb 2+ (aq) + 2I (aq) PbI 2 (aq) D Pb + (aq) + I (aq) PbI(s) Your answer 14 Hydrochloric acid is a strong acid. Its ph is 0.22 at a concentration of 0.60 mol/dm³. What is the ph at a concentration of 0.06 mol/dm³? A 0.78 B 0.022 C 1.22 D 2.20 Your answer
13 SECTION D Higher 15 This question is about separation techniques. (a) A student wants to find out which substances are present in two mixtures, M 1, and M 2. He makes a chromatogram of the two mixtures. He also makes a chromatogram of some substances he thinks may be in the mixtures. Look at the chromatogram from the experiments. solvent front M 1 M 2 A B C unknown mixtures M 1 and M 2 known single substances A, B and C (i) Calculate the R f values for B and for the first spot in mixture M 2. Use a ruler to help you. Write your answers to two significant figures.......... [2] (ii) Use your answers to part (i) to explain whether mixture M 2 contains substance B....... (b) The student concludes that mixture M 1 contains substance A. What other conclusion can he make from the chromatogram of mixture M 1?... Turn over
14 16 This question is about atomic structure. (a) A scientist called J.J. Thomson suggested that atoms are spheres of positive charge with electrons dotted around inside. This was called the plum-pudding model. Two scientists, Geiger & Marsden, did experiments to test the plum-pudding model. They directed beams of positively charged alpha (α) particles at thin gold foil. Look at the diagram of their results. incident α particles target foil atom nucleus Their results showed that: most of the particles went straight through the foil some of them were deflected from their path. Describe what these observations showed about the structure of the atom.... [2]
(b) Complete the table to show the relative charge and relative mass of each particle. 15 Particle Relative charge Relative mass Proton Neutron Electron [2] (c) Iron has an atomic number of 26. Calculate the mean mass of an atom of iron. Give your answer to three significant figures. (Avogadro constant = 6.022 10 23 atoms per mole). Mean mass =... g [2] Turn over
16 17* An oxygen isotope can be shown as 18 8 O Describe what can be deduced from this information about the structure of this oxygen isotope and the position of oxygen in the Periodic Table.. [6]
17 18 A student is making zinc chloride. (a) Look at the method he uses. 1. Measure 50 cm 3 of dilute hydrochloric acid into a beaker. 2. Add a 1 cm piece of zinc metal. 3. Heat the mixture until crystals of zinc chloride are made. The method does not make a pure dry sample of zinc chloride. Write about the improvements that the student should make so that: the reaction is complete pure, dry zinc chloride can be separated from the reactants.... [2] (b) Zinc reacts with chlorine to form zinc chloride. Zn + Cl 2 ZnCl 2 (i) Explain, in terms of electrons, which substance is oxidised in this reaction....... [2] (ii) Construct a balanced ionic equation to show the change that happens to zinc.... [2] Turn over
18 19 A student adds 50 cm 3 of 0.10 mol/dm 3 sodium hydroxide solution, 5 cm 3 at a time, to 25 cm 3 of ethanoic acid. She measures the ph of the mixture after she has added each 5 cm 3. She plots a ph curve. Look at her graph. ph of mixture 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 5 10 15 20 25 30 35 40 45 50 volume of sodium hydroxide (cm 3 ) (a) Explain, in terms of the hydrogen ion concentration, why the ph increases from 3 to 6.... (b) The student uses 0.10 mol/dm 3 ethanoic acid in her experiment. 0.10 mol/dm 3 is a dilute solution. Ethanoic acid is a weak acid. Explain the terms dilute and weak in relation to 0.10 mol/dm³ ethanoic acid. dilute... weak...... [2]
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