Angel International School - Manipay 3 rd Term Examination July, 2015

Transcription

1 Grade 08 Angel International School - Manipay 3 rd Term Examination July, 2015 Chemistry Duration: 2 Hours Index No:- Part I Choose the correct answer and underline it. 1. Which of the following correctly names the process and the gas? Name of process Gas evolved a. combustion Carbon dioxide b. combustion Oxygen c. fermentation Carbon dioxide d. fermentation Oxygen 2. Which of the above pieces of apparatus is best used for measuring the volume of a gas given off during a reaction? A B C D a. A b. B c. C d. D 3. Zinc displaces copper from aqueous copper (11) chloride and magnesium displaces zinc from aqueous zinc sulphate. What is the order of decreasing reactivity of copper, magnesium and zinc? Most reactive least reactive a. Zn, Mg, Cu b. Cu,Zn, Mg c. Mg, Zn, Cu d. Zn, Cu, Mg 4. A student sterilized a sample of water by bubbling a gas through it. The gas was.. a. Carbon dioxide c. Hydrogen b. Chlorine d. Nitrogen 5. Which of the following hazard warning signs should appear on a cylinder of hydrogen? a. Toxic b. Corrosive c. Oxidizing agent d. Flammable 1

2 6. Which is describing as a deadly gas? a. Carbon dioxide b. Carbon monoxide 7. What is the colour of copper carbonate? a. Green b. Black c. Nitrogen oxide d. All of the above c. Grey black d. Purple 8. What are the gases in early atmosphere? a. Water vapour, carbon dioxide, nitrogen b. Oxygen, water vapour, nitrogen c. Oxygen, carbon dioxide, nitrogen d. carbon monoxide, nitrogen, sulphur 9. What are the productions of photo chemical reaction? a. Ozone, oxygen b. Ozone, peroxyacetyl nitrate c. peroxyacetyl nitrate,carbon dioxide d. Oxygen, carbon dioxide 10. Which metal is damaged the nervous system when was inhaled? a. Lead c. Platinum b. Copper d. Gold 11. What are the material catalytic converter made of.. a. Lead, copper c. Platinum, lead b. Platinum, rhodium d. All of the above 12. Which are most harmful pollutants in water? a. Poly chlorinated biphenyls, heavy metals b. Proxy acetyl nitrate, smog c. Soot and smog, heavy metals d. None of the above 13. Which of the following damage the land environment? a. Rubbish, pesticides and extraction of raw materials b. Chemicals, rubbish and fertilizer c. Heavy metals, extraction of raw materials and rubbish d. All of the above 14. Which of the electrode is in a dry cell? a. Carbon b. sugar c. Mercury d. ethanol 15. What are the substances in an electrolyte paste? a. Manganese dioxide, powdered carbon b. Copper dioxide, sulphur dioxide c. Zinc, carbon solid d. Carbon solid, sulphuric acid 2

3 16. Which of the following can cause acid rain? a. Soil erosion b. Industrial smokestacks c. A decrease in the ozone layer d. Clear cutting forests 17. released when coal is burned contributes to the production of acid rain. a. Nitrogen c. Sulfur b. Carbon d. Carbon dioxide 18. Lakes with ph of. Cannot support most life. a. 5 b. 8 c. 10 d Incomplete burning of petrol or diesel in vehicles creates.. gas, which is very poisonous. a. Carbon dioxide b. Carbon monoxide c. Methane d. Ozone 20. Combustion of coal in power plant produces mainly.. which is a major pollution of air. a. Sulphur dioxide c. Methane b. Nitrogen oxide d. Chlorofluoracarbon 21. Which gas is responsible for depletion of ozone layer around earth which protects us from harmful ultraviolet rays? a. Chlorofluoracarbon c. Oxygen b. Nitrogen oxide d. Nitrogen 22. The diagram below a ball of steel wool placed inside the end of the test tube. The test tube is inverted in a beaker of water, trapping the air inside. What was the level of the water after several days? a. A b. B c. C d. D 23. A student made some chlorine by the reaction between concentrated hydrochroric acid and Potassium manganite (vii). Chlorine is more dense than air and soluble in water. Which of the following methods of collection is most suitable for chlorine? a. A b. B c. C d. None of the above 3

4 24. Which gas is primarily responsible for greenhouse effect i.e. global warming? a. Hydrogen dioxide b. Carbon dioxide c. Chlorofluoracarbon d. Sulphur dioxide 25. Excess acidity caused by acid rain can be neutralized by adding a. More fertilizers b. By removing the acidified soil c. By adding P 2 O 5 d. By adding lime 26. A student added aqueous sodium hydroxide to a salt X. On warning a gas was evolved which turned litmus blue. What ion was present in X? a. Cl - c. NH 4 + b. H + - d. NO Fractional distillation is used to.. a. Separate the elements b. Separate the molecules in petrochemicals c. Extract some metals d. Generate electricity 28. Which is not use of hydrogen? a. Making margarine b. Rocket fuel c. Manufacture of plastics d. Extraction of titanium 29. The diagrams show four experiments which were done to investigate the rusting of the iron nails. a. I and II b. I and III c. I and IV d. II and III 30. Sulphuric acid is made by a. Haber process b. Electrolysis c. Contact process d. Electricity (30 1=30 Marks) 4

5 Part 2 1) Chemical weathering, climate,acid precipitation, outer surface, erosion, rust, parent rock, abrasion, soil structure, soil conservation, humus 1. When rocks break down because of chemical reaction it is called.. 2. The same kind of weather in a place over a long time is its. 3. When plants and animals decay forms in the soil. 4. A way to keep soil fertile by protecting it from erosion is called.. 5. When rocks are ground and worn away by rocks and sand it is called 6. Rain, sleet or snow with high concentration of acids is called. 7. The arrangement of soil particle is known as. 8. A rock formation that soil comes from is called 9. Where does the weathering of a rock take place. 10. Oxidation causes (10 1=10 Marks) 2) a. What is an Acid Rain?... (3) b. Write the equation for this? (3) c. How does Acid rain affect the environment? i. Aquatic ii. Forests iii. Human health... iv. Materials (10 marks) 5

6 3) (A) A constant current was passed through aqueous copper (ii) Sulphate using inert electrodes as shown in the diagram below. Copper was deposited at one of the electrodes. a. Name a suitable material for the inert electrodes.. (1) b. At which electrode was copper deposited D or E?. (1) c. What was seen at the other electrode and name that... (1) (B) A student used carbon electrodes. After few minutes a pink solid is deposited on one electrode and a gas evolved at the other electrode. A B Carbon electrodes Copper(II) sulphate solution a. At which electrode, A or B, is the pink solid deposited?.. (1) b. Name this pink solid (1) c. Name the gas evolved at the other electrode (1) d. Give a test for this gas i. Test. ii. Result.. (2) e. How does the colour of the electrolyte change during the electrolysis? iii. From. to (1) f. Eventually, no more of colour solid formed. Instead,a gas is given off from the electrode iv. Name this gas.. (1) g. Give a test for that v. Test. vi. Result.. (2) 6

7 h. What are electrodes, electrolytes and electroplating? vii. Electrodes...(2) viii. Electrolytes... (2) ix. Electroplating (2) i. What is the use of electrolysis?.(1) j. Why electroplating is important?.(1) (20 marks) 4) A student separated two alkanes, hexane (69 0 C) and heptanes (98 o C), using the apparatus shown below. a. i. Name the piece of apparatus labeled M. ii. What is it used for? iii. Name the piece of apparatus labeled N. iv. What is it used for? b. What was the reading on the thermometer when the first few drops of distillate appeared in the beaker? (1) c. How did student know when all the first alkane had distilled over? (1) (06 Marks) 7

8 5) Write the equation for each of the following and write their two uses also. d. Production of SO 2 i. Write two uses of this gas e. Production of SO 3 i. Write two uses of this gas f. Manufacture of NaCl i. Write two uses of this salt g. Production of H 2 SO i. Write two uses of this acid h. Manufacture of ammonia i. Write two uses of this gas i. Production of HNO 3... i. Write two uses of this acid (24 Marks) ***** 8