Index Register Class number number Name IMADUDDIN SCHOOL Second Term Examination 2017 GRADE 9 CHEMISTRY 5070/02 Paper 2 Theory Nov 2017 TIME 1 hour 30 minutes INSTRUCTIONS TO CANDIDATES Write your name, class, index number and register number in the spaces at the top of this page and on any separate answer paper used. Section A Answer all questions. Write your answers in the spaces provided on the question paper. Section B Answer any three questions Write your answers in the space provided. INFORMATION FOR CANDIDATES The intended number of marks is given in brackets [ ] at the end of each question or part question. A copy of the Periodic Table is provided. Examiner s SECTION A B7 B8 B9 B10 This question paper consists of 12 printed pages. IMADUDDIN SCHOOL [Turn over
2 Section A Answer all the questions in this section in the spaces provided. The total marks for this section is 45. A1 Choose from the following words to answer the questions given below. Zinc oxide Pipette Sublimation Hydrogen Potassium manganate (VII) Burette Calcium oxide Methane Oxygen Each word can be used once, more than once or not at all. (a) The process of solid carbon dioxide changing to gaseous carbon dioxide when heated... (b) An oxide, which is amphoteric..... (c) The product formed at the cathode during the electrolysis of acidified water... (d) A powerful oxidising agent....... (e) A piece of apparatus most suitable for transferring exactly 25.0cm 3 of liquid.... (f) A gas that supports combustion...... (g) An element having only one electron in its atom. [Total: 7]
3 A2 (a) The following paragraph is a brief outline of how to prepare copper(ii) sulfate crystals in a laboratory. Fill in the blanks. Add one spatula full of copper(ii) oxide to 50cm 3 of dilute acid. When it has reacted, add further amounts (in excess) until no more will dissolve. Then the mixture to get the filtrate. Heat the filtrate and allow it to cool. Filter off to get the crystals.. the crystals in between filter papers. [3] (b) Why is excess copper(ii) oxide added into the acid?.... [1] (c) What will be the colour change if hydrated copper (ii) sulfate were heated?... [1] (d) Name two other salts that can be prepared by the method described in (a)..... [2] [Total: 7] A3. The diagram below shows the outer shell of one atom of an element R. x x R x x x x (a) In which Group of the Periodic Table does element R belongs to?...... [1]
4 (b) Draw a dot and cross diagram to show the bonding between R and magnesium. [Note: show only outer shell electrons.]. [3] (c) Write the formula for the compound of R with hydrogen..... [1] (d) What type of bonding will there be in the compound of R and hydrogen?... [1] (e) Explain why a molten solution of compound R and magnesium conducts electricity and not the solid compound............. [2] [Total: 7]
A4 The three states of matter are solid, liquid and gas. The diagram below shows how the particles are arranged in these three states 5 Freezing B A C (a) State the name given to the changes: (i) A.... (iii) C... (ii) B. [3] (b) Describe the movement of particles in liquid..... [1] (c) State what happens to the temperature during the change of state B. Explain.. [2] [Total: 6] A5 Sodium reacts with water to produce hydrogen and sodium hydroxide (a) Construct a balanced chemical equation, including the states, for this reaction. [2] (b) Magnesium carbonate reacts with dilute nitric acid to give carbon dioxide. (i) Complete the following reaction by writing the other products that are formed in this reaction MgCO3(s) + 2HNO3(aq) CO2 (g) + + [2]
6 (ii) In an experiment a student used 2g of magnesium carbonate with excess dilute nitric acid. Find the maximum volume of carbon dioxide that will be produced in this reaction..... [2] [Total: 6] A6 This question is about ammonia and fertilisers. Ammonia is produced by a reversible reaction. Figure 1 shows a flow diagram for the Haber process Figure 1 Nitrogen gas Hydrogen gas Reactor containing iron Mixture of gases (nitrogen, hydrogen and ammonia) (a) Write a balanced equation for the production of ammonia. [1] (b) (i) Name one source of nitrogen and hydrogen gas Nitrogen... Hydrogen... [2] (ii) Suggest why air must not get into the reactor.... [2] (c) Calculate the percentage by mass of nitrogen in ammonia (NH3).
7 [Ar: N = 14, H = 1]... [2] (d) A neutral solution can be produced when ammonia reacts with an acid. Give the ph of an ammonia solution. ph. [1] (e) Farmers use ammonium nitrate as a fertiliser for crops. Rainwater dissolves ammonium nitrate in the soil. (i) Explain the environmental effect on increased use of fertilizers.. [4] [Total: 12]
8 SECTION B. Answer any three questions from this section B7 (a) When aqueous solution of germanium(ii) chloride and iron(iii) chloride are mixed, the following reaction occurs. GeCl2 + 2FeCl3 2FeCl2 + GeCl4 (i) Is the germanium(ii) chloride acting as an oxidising agent or reducing agent?... [1] (ii) Define the term oxidation using the idea of oxidation numbers. [1] (b) Magnesium metal reacts with dilute sulfuric acid to form magnesium(ii) sulfate and hydrogen gas. (i) Write a balanced chemical equation for the reaction.... [1] (ii) Did magnesium metal get oxidised or reduced?... [1] (c) Silver nitrate reacts with acidified sodium chloride to give a precipitate of silver chloride according to the equation below. AgNO3(aq) + NaCl(aq) AgCl(s) + NaNO3(aq) (i) State the colour of the precipitate. [1] (ii) Is the reaction a redox reaction? Explain your answer.
9... [2] (iii) Write an ionic equation for the reaction. [1] (d) Find out the oxidation number of chromium, (Cr) in potassium dichromate(vii), K2Cr2O7. [2] [Total: 10] B8 Air is a mixture of gases. The exhaust gases from motorcars contain many pollutants. (a) Define with an example, what is a pollutant?... [2] (b) Write a balanced chemical equation to show the catalytic conversion of carbon monoxide into carbon dioxide using oxygen....... [2] (c) Explain the effect of carbon dioxide as a pollutant....... [2] (d) Name another pollutant from car exhaust.. [1] (e) Name another pollutant that is not from car exhaust.. [1]
10 (f) What could be used to reduce the emission of pollutants from car exhausts?. [1] (g) One of the problems of polluting gases is formation of acid rain, which acidifies the lakes and kills the aquatic life. Suggest a way to prevent this.. [1] [Total: 10] B9 Aqueous potassium chloride is prepared by titrating a strong acid with a strong alkali. (a) Name the acid and alkali that is used to prepare this salt.. [2] (b) Write a chemical equation for this reaction..... [2] (c) Explain why this method is suitable for the preparation of this salt...... [2] (d) Suggest a suitable indicator for this reaction. What would be the colour change of this indicator if the alkali was taken in the flask?. [2] (e) In this titration, 20.0 cm 3 of 1.0 mol/dm 3 of the alkali was used. Calculate the volume of 2.0 mol/dm 3 acid needed to neutralise the alkali.
11..... [2] [Total: 10] B10 The diagram represents an experiment in which an electric current is being passed through dilute sulfuric acid. A B (a) Give the name of the products A & B evolved during the electrolysis. [2] (b) Give the formulae of all the ions present in this solution. Construct an equation for the reaction at each electrode and describe the test for any gas evolved.
12. [5] (c) Dilute sulfuric acid can be used to remove rust, iron(iii) oxide, from iron in a known as pickling. (i) Write the equation for the reaction between iron(iii) oxide and sulfuric acid. [1] (ii) Calculate the mass of rust which can be removed by reaction with 49 g sulfuric acid.. [2] [Total: 10]