YEAR 9 (13+) SCHOLARSHIP. February 2013 for entry in September 2013 SCIENCE FACULTY 2. Biology, Chemistry, Physics. Your Name: Your School:..

Transcription

1 YEAR 9 (13+) SCHOLARSHIP February 2013 for entry in September 2013 SCIENCE FACULTY 2 Biology, Chemistry, Physics Your Name: Your School:.. Time allowed: 1 hour Total marks: 70 Equipment needed: Pen, pencil and ruler. You may use an eraser if needed. Information for candidates: 1. Write your name and school on this page. 2. Write all of your answers on the question paper in the space provided. 3. The marks for each question or part question are indicated in brackets. 4. Answer ALL NINE QUESTIONS in SECTION A and ONE QUESTION ONLY from SECTION B

2

3 SECTION A (Biology, Chemistry and Physics) ANSWER ALL NINE QUESTIONS IN THIS SECTION 1. Figure 1 shows a typical animal cell and a typical plant cell. Figure 1 a) Name the parts of the cells labelled A and B [2] A. B. b) Label on the diagram, with a letter C, another structure that occurs in both cells. [1] c) For each of the following types of cell, state one way in which it is different from the animal cell in Figure 1. State the function of each type of cell. (i) cell lining the trachea (windpipe) [2] Difference Function (ii) sperm cell [2] Difference Function 1

4 d) What is the name given to a group of cells of one particular type? [1] e) From your answer in (d), give a named example one type of this structure found in a plant and one in an animal [2] Plant example; Animal example: 2. A study was carried out to compare the amount of tooth decay in the children of two different towns. Town A had drinking water containing fluoride at a concentration of 2 parts per million. Town B had no fluoride in its drinking water. Figure 2 shows the results of the study, but the graph is incomplete. Figure 2 a) Complete figure 2.1, using the following data. [2] Town Number of decayed % children teeth A 2 13 B 2 9 2

5 b) For town B, state the percentage of children with three decayed teeth. [1] c) For town A, calculate the total percentage of children with less than five decayed teeth. Show your working. [2] d) What conclusion relating to the effect of fluoride, can be drawn from this study. [1] e) Based on your conclusion, what recommendation should be given to town B? [1] f) Explain why some people may object to this recommendation [1] g) How can diet affect tooth decay and what recommendations would you make to someone who doesn t understand the effect of diet on their teeth? [2] [Total: 20 marks] 3

6 3. A student wanted to investigate physical and chemical changes and heated four different chemicals in a crucible. The results that she collected are given below: Experiment Chemical Observations Change in mass The silvery metal burned with a Magnesium 1 bright white light. A Increase (Mg) white solid was formed. 2 Potassium permangan ate (KMnO4) 3 Iodine (I2) 4 Potassium chlorate (KClO3) Purple crystals turned black. A colourless gas was given off. Grey crystals. At the end of the experiment there were also grey crystals on the inside of the lid of the crucible. White/colorless crystals. No significant change in appearance but the amount of crystals got less. Decrease No change Decrease a) (i) The magnesium reacted with one of the gases in the air. Name this gas. [1] 4

7 (ii) Complete the word equation for the chemical reaction that occurs in Experiment 1. [1] Magnesium + (iii) Explain why the mass increased in this experiment. [1] b) Suggest in which experiment(s) a physical change occurred by completing the following sentence. [1] A physical change occurred in experiment(s) c) (i) In experiments 2 and 4 a gas was given off. It was the same gas in each case. Suggest the identity of the gas given off. [1] (ii) Describe a chemical test to identify the gas in (c)(i). [2] Test Result d) Some of the chemicals in the table are elements. Identify the ones that are elements. [1] e) Explain what happened in experiment 3. [2] 5

8 4. The diagram shows a representation of a chemical reaction. Use the key to help you write a word equation and symbol equation for this reaction. [3] Word equation Symbol equation 5. a) The method used to separate the substances in a mixture depends on the properties of the substances in the mixture. Methods that are commonly used are: distillation fractional distillation filtration crystallization chromatography (each word may be used once more than once or not at all) For each of the following, name a suitable method for obtaining: (i) water from potassium chloride solution [1] (ii) water from a mixture of calcium carbonate and water [1] (iii) a red food dye from a mixture of coloured food dyes [1] 6

9 b) Rock salt is an impure form of sodium chloride that is used extensively for de-icing roads. It is typically over 90% sodium chloride with impurities that are mainly of a similar chemical composition to sand. Assuming that rock salt just contains sodium chloride and sand, describe an experimental procedure that could be used to produce pure solid sodium chloride from rock salt. [4] [Total: 20 marks] 7

10 6. The diagram shows the Sun and the orbits of the five inner planets. The distances (but not the sizes of the Sun and Jupiter) are to scale. a) On the diagram, draw a dot to show the Earth s position when Earth and Jupiter are moving parallel to each other and in the same direction. Label the dot E. [1] b) As Jupiter moves in its orbit, it appears to move across the pattern of stars in the background. When Jupiter and the Earth are moving parallel to each other, Jupiter appears to move backwards across the pattern of stars. Explain why. [1] c) The light from the Sun takes about 8.3 minutes to reach the Earth. Using the diagram above, estimate how long it takes for light to travel from Jupiter to the Earth when they are the shortest possible distance apart. Show your working. [2] 8

11 7. Alex makes an electromagnet by winding insulated wire around an iron nail and then connecting the wire to a power supply. She uses the electromagnet to pick up some steel paper-clips. Alex predicted: The more turns of wire around the iron nail the stronger the electromagnet becomes. a) (i) Give the one factor she should change as she investigates her prediction. [1] (ii) Give one factor she should keep the same. [1] (iii) Describe how she could use the paper-clips to measure the strength of the electromagnet. [1] b) Alex wrote a report of her investigation. What would an odd result suggest? [1] 9

12 c) (i) Which size paper-clips would Alex use to make her results more accurate? [1] Tick the correct box. (ii) Give a reason for your choice. [1] 8. a) The diagram below shows a fish tank. [3] The surface of the water acts like a mirror. The fish can see the snail reflected in the surface of the water. Draw a ray of light which passes from the snail, and reflects from the surface, to show how the fish can see the snail. Use a ruler and put arrows on the ray of light. 10

13 b) Andrew is looking at the snail. When a ray of light passes from water to air it changes direction. (i) Draw a ray of light from the snail to Andrew to show how Andrew can see the snail. [2] (ii) What is the name given to this change in the direction of a ray of light? [1] 9. The diagram shows a boat using an echo sounder. It sends a pulse of sound waves which is reflected from the sea bottom. The reflected sound waves are detected by a sensitive microphone. The time between sending and receiving the pulse is s. The device calculates the depth of the sea, using the speed of sound in sea water, which is 1500 m/s. 11

14 a) Calculate the depth of the sea. Show your working. [2] b) The boat moves into very deep water. Explain why the reflected pulse is too weak to be detected. [1] c) The boat s echo sounder could not be used in an aeroplane to measure its height above the ground unless it had been modified. Explain why the device will not give correct heights above the ground. [1] [Total: 20 marks] 12

15 SECTION B (Biology, Chemistry and Physics) ANSWER ONE QUESTION ONLY FROM SECTION B 1. The seaweed, Caulerpa taxiflora, lives in tropical oceans, but is now also found in the Mediterranean Sea, where it grows at twice the rate of local seaweeds. As a result, the local seaweeds are becoming rare. Although not poisonous, Caulerpa, produces a chemical in its cells that makes it inedible to Mediterranean herbivores, such as sea urchins. They do not feed on it and their numbers are decreasing. Carnivorous fish populations have also decreased by up to 50%. Marine conservationists are very concerned. At first they used chlorine to kill Caulerpa but are now considering the introduction of tropical sea slugs (herbivorous molluscs). Caulerpa is part of their natural diet. a) Suggest why the local seaweeds are becoming rare. [2] b) Sea urchins are herbivores. Define the term herbivore. [1] c) In the second paragraph, suggest why the populations of carnivorous fish have decreased by up to 50%. [2] 13

16 d) Suggest why using chorine to kill Caulerpa might not be a good idea. [1] e) Suggest why conservationists are concerned about the effects of Caulerpa on other organisms in the Mediterranean. [2] f) Explain how the introduction of herbivorous sea slugs from the tropics could be effective in re-establishing a balanced ecosystem, [2] [Total: 10 marks] 14

17 2. Anjali carried out an investigation into the reactivity of metals by adding different powdered metals to 25 cm 3 of copper sulfate solution in a polystyrene cup. In the first experiment she measured the initial temperature of the copper sulfate solution, added zinc powder, stirred rapidly and then measured the maximum temperature reached. The results of her experiment are shown in the thermometer diagrams. Initial temperature / o C Maximum temperature / o C a) State the initial and maximum temperatures in this experiment: [1] Initial temperature Maximum temperature b) Anjali then repeated the experiment with magnesium powder and iron powder. The results are shown in the table. Metal Initial temperature / o C Maximum temperature / o C magnesium iron (i) Work out the change in temperature for each experiment: [1] Metal zinc magnesium iron Change in temperature / o C 15

18 (ii) The amount of heat energy given out in each experiment can be worked out using the formula. [2] Heat energy evolved (kj/mol) = 25 x 4.18 x temperature change x 1000 Calculate the heat energy evolved in each experiment. Metal zinc magnesium iron Heat energy evolved / kj/mol (iii) Plot this data as a bar chart on the grid below. [3] 16

19 (iv) Suggest an explanation for these results. [1] (v) The literature value for the heat evolved when zinc reacts with copper sulphate solution is 210 kj/mol. Suggest two reasons why the value that Anjali calculated from her experiment is lower than the literature value. [2] [Total: 10 marks] 17

20 3. Jack and Daryl dropped a steel ball into trays of damp sand. They measured the depth of the craters made by the steel ball. not to scale Their results are shown in the table below. height the ball was dropped from (cm) depth of crater (cm) Jack s results Daryl s a) Use information in the table to answer the questions below. (i) What was the independent variable that Jack and Daryl changed in their investigation? [1] (ii) Why was Jack s investigation better than Daryl s? [2] b) Looking at the results in the table. What conclusion would you draw from Jack and Daryl s results? [2] 18

21 c) Daryl said that they made sure the investigation was fair. Suggest two variables they must have kept the same to make their investigation fair. [2] d) (i) Jack removed the steel ball using his fingers. Then he measured the depth of the crater. Daryl said he should use a magnet instead of his fingers. Explain why using a magnet to remove the ball would improve the investigation. [1] (ii) Jack said that the ball could be dropped using an electromagnet instead of dropping it by hand. Explain why this would improve the investigation. [1] (iii) Suggest one more improvement that could be made to the investigation. [1] [Total: 10 marks] 19