GRE 8 NTURL SIENES SIENE OMPONENT JUNE EXM 2007 EX: GR MOERTOR: KK MRKS: 150 TIME: 1 1/2 Hours EQUTIONS: m h d h H = and = or = v H d INSTRUTIONS and NOTES: This paper consists of 9 pages of questions, a periodic table and a 5 page answer sheet. Use a pencil where it is required. calculator may be used. Use the nswer sheet for LL questions. QUESTION 1 Four possible answers indicated by,, and are supplied with each question. hoose only that answer which, in your opinion, is the correct or best one and mark the appropriate block on your answer sheet. Use a pencil ONLY. Each question has only one correct answer. If more than one block is marked, no marks will be awarded for that answer.
1.1 Two immiscible liquids can be separated without heating, by using: a separating funnel. a Liebig condenser. filtration. distillation. 1.2 rownian motion occurs in liquids only. occurs in gases only. occurs in both liquids and solids. occurs between smoke and pollen grains. 1.3 n example of a single compound is carbon powder. calcium chloride. a solution of sugar in water. argon gas. 1.4 block of wood has a density of 0,5 g/cm 3. It is floated in the liquids indicated. The block will float highest in 1.5 The density of a substance is the LIQUI ENSITY Ether 0,7 g/cm 3 lcohol 0,8 g/cm 3 Water 1,0 g/cm 3 arbon tetrachloride 1,6 g/cm 3 volume of a unit mass of the substance. product of the mass and a unit volume of the substance. mass of a unit volume of the substance. ratio of the weight of the substance to its volume. 1.6 The atom consists of a centrally situated positively charged electron. proton. nucleus. nucleon. Page 2 of 9
1.7 Which of the following combinations is correct? Symbol Name Valency O Oxygen +2 hlorine 1 Ph Phosphorous 3 Mg Magnesium +2 1.8 If Sulphur (S) has a valency of 2 and arium (a) a valency of +2, then the formula of the substance formed when a and S combine chemically is: as a 2 S 2 as 2 a 2 S 2 1.9 burette which has a maximum reading on it of 50 ml gives a reading of 18 ml when it is partly filled with water. Water is then run out of it until the new reading is 35 ml. The volume of water run out is 18 ml 35 ml 15 ml 17 ml 1.10 120 cm is equal to 0,012 m 0,12 m 1,2 m 12 m 1.11 The volume reading on the measuring cylinder shown alongside is: 85 ml. 65 ml. 64 ml. 70 ml. 100 ml 20 100 80 60 40 20 1.12 The three phases of matter can be arranged as follows in order of decreasing attractive forces between the particles: gases, liquids, solids. liquids, solids, gases. solids, liquids, gases. solids, gases, liquids. Page 3 of 9
1.13 The graph below represents the progress shown when ice at 5 is heated through to steam at 100. The region on the graph that shows the HETING of IE is best given by the letter,, or. Temp ( ) 100 90 80 70 60 50 40 30 20 10 0 10 4 8 12 16 20 24 Time (minutes) 1.14 centrifuge is a device that is best used to separate a mixture consisting of substances that have similar densities. solid particles suspended in a solution. two miscible liquids. liquids and solids only. 1.15 ccording to the particle model of matter, all matter consists of energy. molecules. small particles in continuous motion. colliding particles at high temperatures. 15 x 2 = 30 Page 4 of 9
QUESTION 2 NSWER ON THE NSWER SHEET Fill in the missing word or phrase that best describes or completes the sentences below: 2.1 is the phase change that occurs when a solid goes straight to a gas without turning into a liquid. 2.2 The method of separation that is used when the different colours contained in ink diffuse when they come into contact with a liquid is called. 2.3 The name of the symbol Mn is. 2.4 chemical combination of two or more elements is called a. 2.5 The SI unit of mass is the. [10] QUESTION 3 NSWER ON THE NSWER SHEET Next to the appropriate number from column, write down on your answer sheet the letter from column that best matches the description given in column. n option can be used more than once. OLUMN OLUMN 3.1 gas turns into a liquid. Freezing 3.2 The valency of oxygen. S 3.3 Process of removing alcohol from water. Neon 3.4 Symbol of the element sodium. 1 3.5 Number of centimetres in a metre. E Na 3.6 Name of the substance with symbol, N. F istillation 3.7 1 cm 3 =.. mm 3 G Fractional distillation H ondensation I 1000 J 100 K 2 L Nitrogen [14] Page 5 of 9
QUESTION 4 NSWER ON THE NSWER SHEET 4.1 quantity of ice was placed into a beaker that contained a thermometer. The beaker was then placed on a tripod and the contents heated with a unsen burner. Temperature measurements were taken every minute and recorded in a table as shown below. This data was then plotted as shown alongside the results. Note that the graph is incomplete. Now answer the following questions on your answer sheet: Time (minutes) Temperature ( ) 0 0 1 0 2 1 3 1 4 5 5 11 6 17 7 23 8 30 9 40 10 50 11 56 12 69 13 76 14 83 15 89 16 94 17 97 18 100 19 100 20 100 120 100 80 60 40 20 0 0 5 10 15 20 25 20 4.1.1 On the answer sheet, provide a suitable heading for the graph. (2) 4.1.2 On the answer sheet, provide suitable labels for the x and y axes. (4) 4.1.3 On the answer sheet, complete the graph IN PENIL by drawing in a best fit. One point is incorrect remember to exclude it from your best fit. (4) 4.1.4 One temperature value was recorded incorrectly. (a) What was the corresponding time for this incorrect reading? (2) (b) What should the temperature reading have been? (2) 4.1.5 What do the flat parts of the graph represent between (a) times 0 to 3 minutes? (2) (b) times 18 to 20 minutes? (2) 4.1.6 Why are the graphs flat between these two times? (2) [20] Page 6 of 9
4.2 You are given a beaker containing sugar dissolved in water mixed with sand, iron nails and copper coins. The table is redrawn on the answer sheet. omplete it to show the order in which you would separate the different underlined substances to dryness so that as little water is wasted as possible. The order must be logical and as practical as possible. You cannot add anything to the mixture. ORER 1 2 3 4 5 SUSTNE/S SEPRTE METHO OF EXTRTION 6 [12] 4.3 The apparatus below is used to separate a solvent from its solution. water outlet water inlet 4.3.1 Give an example of a mixture that can be placed in the distillation flask. (2) 4.3.2 Using your answer from 4.3.1, name the substance which is represented at? (2) 4.3.3 What is the general name given to the apparatus above? (2) [6] 4.4 On your answer sheet are two columns, one is headed Metals and the other Nonmetals. Tabulate three differences between them. [6] Page 7 of 9
4.5 Name the elements represented by the following symbols. 4.5.1 4.5.2 Zn 4.5.3 u [6] 4.6 Write down the symbols of the following elements. 4.6.1 Platinum 4.6.2 alcium 4.6.3 opper [6] 4.7 This question deals with elements and compounds. 4.7.1 efine an element (2) 4.7.2 Give the NME of a metal element that is a liquid at room temperature. (2) 4.7.3 Give the NME of a non metal element that is a liquid at room temperature. (2) 4.8 This question deals with the density of different substances. 4.8.1 rectangular solid (one that is shaped like a brick) was found to be 30 cm long, 8 cm wide and 4 cm thick. When put on a balance it had a mass of 7200 g. alculate its density. (5) 4.8.2 measuring cylinder was partly filled with water up to the 51 cm 3 mark. piece of metal of mass 153 g was immersed in the water and the water level rose to the 68 cm 3 mark. alculate the density of the metal. (6) [11] 4.9 In dealing with large numbers in measurement it is often convenient to add a prefix to the unit. Give the correct prefix and abbreviation (Eg: 1000 times has as its prefix, kilo and the abbreviation is, k) for 4.9.1 1000 000 times 4.9.2 1 thousandth [4] 4.10 On a sunny day, a metre rule casts a shadow 55 cm long. What is the height of a tree whose shadow is 48 m long? [5] 4.11 Using your knowledge of valencies, write down the formulae of the substances formed when the following atoms react together. 4.11.1 a and l (2) 4.11.2 K and O (2) [6] [4] Page 8 of 9
4.12 n experiment to show diffusion was done in class at 25. white cloud forms when ammonia and hydrogen chloride gases combine. otton wool with hydrochloric acid loud of ammonium chloride otton wool with ammonia solution 4.12.1 What was the temperature in Kelvin? (2) 4.12.2 What would be noticed if the experiment was done at 70 and not 25? (2) 4.12.3 Explain your observation to 4.12.2. (2) 4.12.4 What is rownian Motion? (3) 4.12.5 part from ammonia gas, hydrogen chloride gas and ammonium chloride, what other particles would be present in order to cause rownian Motion? (1) EN OF PPER TOTL 150 Page 9 of 9