7. In order to allow contraction in cold weather, overhead cables should be A. covered in thick heat insulation. B. warmed occasionally in cold weathe

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1 Mid-Year Examination Integrated Science Form 2 Name : Time allowed: 1hr. 15mins. Class : ( ) Paper total: 100 marks Answer all the questions on the answer sheets provided Section A: Multiple Choice (20 marks) 1. Which of the following substances has the highest density? A. Water B. Iron C. Wood D. Air 2. If the weight of the block below is 2 kg. What is the density of the block? A g/cm 3 B. 10 g/cm 3 C. 20 g/cm 3 D. 200 g/cm 3 3. Which of the following statements about atom is correct? A. Atoms which make up copper are the same as those which make up iron. B. Atoms in all substances are of the same size. C. An atom is the smallest particle of an element that has the properties of that element. D. Atoms in all substances are of the same mass. 4. Hot water has a lower density than cold water. It is because A. The size of cold water particles is bigger than that of hot water particles. B. The size of cold water particles is smaller than that of hot water particles. C. Cold water particles are heavier than hot water particles. D. Hot water particles spread further apart than cold water particles. 5. Gas pressure can be measured using A. an air compressor. B. a Bourdon gauge. C. a Gordon gauge. D. a syringe. 6. If a cup of water is covered with a card and then turned upside down, the card does not fall. Why? A B C D The water sticks the card to the cup. The card is lighter than air. The atmospheric pressure pushes up the card. The water does not have pressure. card 10 cm a cup filled with water 5 cm 2 cm F. 2 I.S. Mid-Year Exam page 1 of 6

7. In order to allow contraction in cold weather, overhead cables should be A. covered in thick heat insulation. B. warmed occasionally in cold weather. C. installed loosely. D.

2 7. In order to allow contraction in cold weather, overhead cables should be A. covered in thick heat insulation. B. warmed occasionally in cold weather. C. installed loosely. D. tensed up in hot season. 8. A ship travels from a fresh water river to the sea. If the temperature of seawater is the same as that of river water, which of the following marks (A to D) best represents the depth of the ship in the sea? The original depth is at position C. A B C D 9. A student spills a chemical on her nylon shirt. Which liquid should she use to remove the chemical? Liquid Nylon Chemical A Soluble soluble B Soluble insoluble C Insoluble soluble D Insoluble insoluble 10. Which of the following government departments is responsible for water purification? A. Environmental Protection Department B. Drainage Services Department C. Food and Environmental Hygiene Department D. Water Supplies Department 11. The following are the steps of growing copper(ii) sulphate crystals (1) Dissolve copper(ii) sulphate powder in a beaker of hot water. (2) Let the solution cool down. (3) Keep on adding the powder until a saturated solution is formed. (4) Tie a piece of thread around a copper(ii) sulphate crystal, and suspend it in the solution. Which of the following is the correct order? A. (4) (2) (3) (1) B. (1) (3) (4) (2) C. (1) (3) (2) (4) D. (4) (1) (3) (2) F. 2 I.S. Mid-Year Exam page 2 of 6

3 12. Which of the following statements about crystals is INCORRECT? A. Crystals are coloured and transparent. B. When a hot, saturated solution cools down rapidly, small crystals are formed. C. When a hot, saturated solution cools down slowly, large crystals are formed. D. Crystals of the same substance have more or less the same shape. 13. Which of the following does NOT form crystals? A. Quartz B. Table salt C. Glass D. Snowflake 14. Which of the following pairs can be distinguished by blue litmus indicator? A. Sodium hydroxide solution and vinegar B. Sodium hydroxide solution and ammonia solution C. Vinegar and hydrochloric acid D. Distilled water and salt solution 15. Which of the following is NOT a property of alkalis? A. They taste sour. B. They feel soapy. C. They are corrosive. D. None of the above. 16. Which of the following substances contain alkalis? i) Indigestion powder ii) Soap solution iii) Yoghurt iv) Washing soda A. I and ii only B. ii and iv only C. ii, iii and iv only D. I, ii and iv only 17. Which of the following is NOT an indicator for acids and alkalis? A. Litmus paper B. Extract of onion C. Vinegar D. ph paper 18. The following table shows the colour of universal indicator in four solutions. Solution W X Y Z Colour Green Purple Yellow Red Arrange the above solutions in descending order of ph values. A. W>Y>X>Z B. Y>X>W>Z C. X>W>Y>Z D. Z>Y>W>X F. 2 I.S. Mid-Year Exam page 3 of 6

4 19. Which of the following is a use of sulphuric acid? A. Used as household cleaners B. Used to make cosmetic products C. Used to make car batteries D. None of the above 20. Which of the following substances contains ethanoic acid? A. Apple B. Vinegar C. Orange D. None of the above Section B: True or False (10 marks) 1. A molecule is a new substance when two or more elements are mixed together. 2. When substances are heated, the particles move about more vigorously and are spaced further apart. 3. All solids contract by the same amount if cooled down equally. 4. Heating can increase the rate of dissolving salt in water. 5. Water covers about half of the Earth's surface. 6. Over 90% of our body mass is made up of water. 7. Only acids are corrosive. 8. The acids found in foods and drinks are weak acids. All weak acids are safe to take in. 9. Some acids can be added to food and drinks to improve the taste. 10. Indicators are dyes which change colour when placed in an acid or an alkali. Section C: Fill in the blanks (20 marks) a. Complete the following table. Name of sub-atomic particle Symbol Charge (relative to that on a proton) (1) p Positively charged (2) n (3) Electron (4) Negatively charged b. There are (5) elements that occur naturally. Scientists can make about 25 more in laboratories. c. In Hong Kong, 20% of our water supply comes from (6) and 80% from (7) river. d. (8) is a chemical that is added to drinking water to help to prevent our teeth from decaying. e. The process in which large solid particles settle at the bottom of a liquid is called (9). f. A substance which can dissolve in a liquid is called a (10), and the liquid in which it dissolves is called a (11). The substance dissolves in the liquid to form a solution. g. (12) is a dye that turns pink when it meets alkalis and remains colourless when it meets acids. h. Lime water is a kind of alkali which contains (13). It turns red litmus paper (14). i. Sodium hydroxide, which is also named (15), is a strong alkali that can remove hardened grease. It can be used as (16). j. Complete the following table. F. 2 I.S. Mid-Year Exam page 4 of 6

5 Section D: Short questions (50 marks) 1 Water is a compound. (a) State the definitions of the following terms: (i) Element (ii) Compound (b) State the two constituent elements of water. (c) Illustrate with ONE example why water is a compound but not a mixture of its elements. 2. Explain why the egg would explode if we boil the egg in the microwave oven. (Hint: A microwave oven can heat up food by heating up the water inside) 3. Read the following article and answer the questions that follow. (a) (b) (c) Mum, I have heard from my friends that we can boil an egg by just putting it into the microwave oven, is that true? Name of Element Chemical Symbols Atomic number (17) (18) 4 (19) Si (20) No! You should never do that! The egg will explode inside the microwave oven. Which part of the fish is responsible for allowing a fish to move up and down? Explain the principle of the rise and fall of a fish. How can a fish stay at a particular level in water? (4 marks) Fish have built-in mechanisms that allow them to move up and down in water. To move up, a fish must increase its volume without significantly increasing its mass. Most fish do this with a structure called a swim bladder, which is expandable. A fish moves up by filling the bladder with oxygen collected from the surrounding water via the gills. The fish will sink when the bladder is completely deflated. (6 marks) (5 marks) 4. Explain the following. (a) A hydrogen balloon will float in air but a balloon that is blown up by ourselves will drop onto the floor. (b) Carbon dioxide can be used to put off fire but helium cannot. (c) A tight metal lid on a glass container can be opened easily after running hot water over it. (d) Black tea changes colour when lemon is added to it. (8 marks) F. 2 I.S. Mid-Year Exam page 5 of 6

6 5. Jennifer has just come home after the school picnic. She is very thirsty but there is no water in the kettle. Therefore, she wants to drink tap water. Jennifer, there are many micro-organisms in the tap water. You can't drink it directly. (a) Do you agree with Jennifer? Explain your choice. (b) Suggest TWO kinds of micro-organisms that may be found in tap water. (c) Suggest ONE disease that will be caused by the micro-organisms in part (b). (d) Chlorine and ozone are chemicals that we may use in water sterilization. (i) State TWO advantages of using ozone over chlorine in water sterilization. (ii) Besides using ozone and chlorine, suggest ONE more method that is commonly used in water sterilization. (8 marks) 6. A student wanted to separate ethanol from an ethanol water mixture. On the right, is a diagram showing just part of the set up of apparatus for carrying out this separation in a school laboratory. (a) Label the parts A, B and C. (b) Complete and properly label this diagram. B (c) (i) Name the process. (ii) State TWO uses of the above process in industry. Glass beads (d) State the function of the following: (i) A (ii) C (iii) Glass beads (e) (i) Which liquid will be collected first, ethanol or water? Explain your Mixture choice. C (ii) State the hazard warning that should be placed outside the bottle of ethanol. (15 marks) 7. Mary is pouring some soft drink into a glass. Many gas bubbles can be seen. (a) What is the gas inside these gas bubbles? (b) The above gas is added to the drink during production. What acid is formed when the gas is dissolved in the drink? (c) Mary notices that the soft drink is slightly sour. However, when it is left aside overnight, it is not sour any more. Briefly explain this phenomenon. (4 marks) --End of paper-- Don t worry, mum. The microorganisms are already filtered by water filter. A Heat F. 2 I.S. Mid-Year Exam page 6 of 6

Have a ph value less than ph 7 Turn blue litmus indicator red Can neutralise an alkali Have a sour taste (WARNING: never taste any chemicals)

Acids and Alkalis ACIDS (acidic solutions) Acids have the following properties: Have a ph value less than ph 7 Turn blue litmus indicator red Can neutralise an alkali Have a sour taste (WARNING: never