Part A: Knowledge Multiple Choice Identify the choice that best completes the statement or answers the question. [35 marks]

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1 Lorne Park Secondary School Practice Exam Teachers: Mr. A. Einstein Ms. M. Currie Mr. I. Newton Length: 1.5 h Part A: Knowledge Multiple Choice Identify the choice that best completes the statement or answers the question. [35 marks] 1. An investigator wants to determine how the diameter of a wire affects how easily electricity flows through the wire, by using wires of different diameters and observing the effect, if any, on the electrical current in the wire. Identify the dependent variable(s) in this experiment. a. diameter of the wires b. electrical current in the wire c. all of the above 2. An experiment in which the independent variable is purposely changed to find out what change, if any, occurs in the dependent variable, is called a(n) a. controlled experiment b. observational study c. correlational study 3. Which of the following is an example of a qualitative observation? a. length b. odour c. mass d. temperature 4. All of the following are abiotic factors, except a. water b. moss c. air d. temperature 5. What are all organisms living in the same ecosystem called? a. population b. community c. species d. family 6. Which cycle relies mostly on photosynthesis for completion? a. water b. carbon c. nitrogen d. biogeochemical 7. Which of the following elements is most difficult for living organisms to obtain? a. hydrogen b. carbon c. nitrogen d. oxygen Page 1

2 8. Which of the following describes the state of an ecosystem with relatively constant conditions over a period of time? a. stabilization c. equilibrium b. succession d. balanced 9. The process of establishing and replacing a community following a disturbance is called ecological a. stabilization b. succession c. equilibrium 10. A species that no longer exists in the wild in a specific area but still lives elsewhere is called a. threatened b. endangered c. extirpated d. extinct 11. A non-native species whose intentional or accidental introduction negatively impacts the natural environment is called a(n) a. predatory species b. invasive species c. competitive species d. nuisance species 12. A student observed an object and reported that it had a mass of 2.80 g, had a length of 6.10 cm, was red in colour on the outside, and was shaped like a cylinder. Which statement is true? a. The student reported two qualitative observations and two quantitative observations. b. The student reported one qualitative observation and three quantitative observations. c. The student reported four qualitative observations. d. The student reported four quantitative observations. 13. The density of gold is 19.3 g/cm 3, whereas the density of aluminum is 2.7 g/cm 3. How would the volumes of equal masses of gold and aluminum compare? a. The aluminum sample would have the greater volume. b. The gold sample would have the greater volume. c. The samples would have the same volume because they have equal masses. d. There is not enough information to make a comparison. 14. A chemist reports to his supervisor a sample of gas has a mass of 0.5 g in a container of 400 cm cm 3. Of the gases in the table, which gas might the unknown be? a. nitric oxide b. nitrogen dioxide c. carbon monoxide d. not enough information to tell 15. An alloy is an example of a a. solution b. mechanical mixture c. pure substance Gas Density at sea level atmospheric pressure and 0 o C nitric oxide g/cm 3 nitrogen dioxide g/cm 3 carbon monoxide g/cm 3 Page 2

3 16. Passing electricity through liquid table salt (NaCl) produces sodium metal and chlorine gas. This experiment shows that table salt is a. a uniform mixture b. a non-uniform mixture c. a compound d. an element 17. Which of the following is an element? a. ammonium chloride b. sodium fluoride c. methane d. boron 18. Rutherford s gold foil experiment showed that a. atoms have a tiny, positively charged nucleus b. atoms are mostly solid c. electrons crowd tightly together at an atom s centre d. all of the above 19. The main evidence that led Bohr to his theory of electron orbits is a. hot materials give off electrons b. there are patterns in the properties of the elements in the Periodic Table c. atoms give off only certain colours when energized by heat or electricity d. tiny positively charged particles pass easily through gold atoms 20. In the chemical formula NaHCO 3, there are a. four different elements b. four non-metallic elements c. three atoms in total d. twelve atoms in total 21. Which would be a correct name for the compound KF? a. potassium fluorine b. potasside fluorine c. potassium fluoride d. potasside fluoride 22. In 26,000 years, Earth s North Celestial Pole will point to Vega, not Polaris as it does now, because a. Vega is moving into a different position than it is now b. Polaris is moving into a different position than it is now c. gravitational influence from the Sun redirects Earth s orbit d. precession redirects the North Celestial Pole 23. Pointer stars are a. the brightest stars in a constellation b. the North and South Stars c. used to find other stars d. used to determine Earth s orbit 24. Why did early astronomers at first not understand what caused retrograde motion? a. They thought planets never reversed their course in the sky. b. They thought planets revolved around Earth. c. They thought there was no difference between planets and stars. d. They thought the Sun s gravity made planets change their orbits. 25. If you studied the night sky from dusk to dawn, what would you notice most? a. a change in the brightness of stars b. constellations staying in the same place c. stars rotating around the North Star d. the number of stars steadily decreasing Page 3

4 26. The biggest difference between Earth and the other planets in the Solar System is a. a rocky surface c. an orbiting moon b. an atmosphere d. large amounts of liquid water 27. In 1965, evidence for the Big Bang theory was accidentally discovered because a. scientists found stars where they didn t expect them b. more matter and energy were being created every day c. scientists thought their telescope wasn t working d. radiation came from one unexpected area of the Universe 28. A light year is a. the distance light travels in a vacuum during a year b. the distance light travels on Earth c. all the light a star produces in a year d. the amount of time it takes light from a star to reach Earth 29. The cloudy images seen in photographs of nebulas are a. star clusters b. dust particles c. individual stars d. nuclear fusion 30. What causes a star to begin contracting as it first begins to die? a. It runs out of fuel and its outward flow of energy decreases. b. It grows in size. c. Its core cools off. 31. Which of the following particles is (are) located in the space surrounding the nucleus of an atom and can be added or removed from atoms? a. proton b. electron c. all of the above 32. A positively charged object is an object with a. more electrons than protons b. fewer electrons than protons c. an equal number of electrons and protons 33. Connecting an object to a large body, like Earth, that is capable of effectively removing an electric charge that the object might have is called a. charging by friction b. charging by conduction c. charging by induction d. grounding 34. Which of the following is an example of an external source for an electric generating station? a. moving water b. steam c. wind d. all of the above 35. The symbol for electric current is a. I b. V c. A d. C Page 4

5 PART B: APPLICATION. Read the passage below and answer the questions in the space provided. [8 marks] Good soil is alive with many different types of organisms and is actually a full ecosystem. A very important organism that makes its home in soil is the earthworm. There can be close to a half ton of earthworms in an acre of living topsoil. There are many benefits that earthworms provide. Earthworms naturally till the soil by tunneling, which provides natural tillage and soil aeration. A field that is naturally tilled by earthworms can absorb up to 10 times as much water as a field without worm tunnels, reducing runoff and allowing the soil to store more water for dry seasons. The increase in the air content of the soil encourages the natural nutrient cycling that feeds plants. However, earthworms do not thrive where regular tillage occurs on a regular basis. When soil is tilled, it causes the soil to be drier, buries the nutrients that the worms typically feed on, and causes the soil to be more susceptible to freezing. All of these can significantly reduce the worm population. Earthworms eat the dead plant material that lies decaying on the surface. Then the nutrient-rich matter is spread throughout the soil by the waste of the worm. The secretions of earthworms are growth stimulants for plants. Between the tillage, the excretions, and the secretions, earthworms make the soil much more nutrient rich than the original soil. Earthworms are an important part of living soil. They help to produce a soil that is excellent for growing plants. 1. What does the word excretions mean in paragraph 3? a. natural substance that is given off from the worm s exterior b. waste that is produced by digested material 2. What makes soil alive? a. Soil is a living organism. b. The plants growing in the soil. a. dry soil b. tilling the soil 4. The word however in paragraph 2 is used to a. introduce an opinion. b. emphasize a contrast c. connect a main idea and an example d. join two ideas that have the same meaning 5. The information in this selection is organized by a. a list of advantages b. a list of disadvantages c. a comparison of viewpoints d. most important to least important c. plant material that the worm spreads by tunneling d. decaying material after the worm dies c. The organisms living in the soil. d. The animals that burrow in the soil. 3. Which of the following will not reduce the worm population in the soil? c. soil that freezes d. leaving soil untouched 6. The tunneling of earthworms helps with all of the following except a. soil aeration b. the nutrient level of the soil c. making the soil more susceptible to freezing d. soil moisture Page 5

6 7. Which of the following ideas link the first and last sentences of this selection? a. More research on earthworms is necessary. b. Living soil is excellent for growing plants. c. Farmers should add earthworms to the soil after each time they till. d. Earthworms replace the need for fertilization. 8. What is meant by the word stimulants in paragraph 3? a. The secretions encourage plant growth. b. The secretions discourage plant growth. c. The secretions activate photosynthesis. d. The secretions allow seeds to germinate. PART C: APPLICATION AND INQUIRY. Answer questions in the spaces provided [40 marks] 1. A candle is lit and placed on a tray so that all of the wax that drips down is caught in the tray. If the melted wax is collected in this manner, will the mass of the candle and tray change over time? Why or why not? [2] 2. A student finds the mass of a steel marble to be g. To find the volume of the marble he submerges it in 25 cm 3 of water and observes that the volume of the water rises to 27.0 cm 3. Calculate the density of the marble, showing your work fully. [2] 3. A 5.00 g sample of a pure-substance powder is heated, and the powder leaves 4.63 g of a shiny, metallic liquid. Is the powder an element or a compound? Explain. [2] 4. Draw a Bohr-Rutherford diagram for a) carbon-14 and b) silicon-29. [6] Page 6

7 5. How many electrons do the alkali metal atoms lose when reacting with water? How many electrons do they have in their outer orbits? Based on the pattern above, what would you predict for the atoms of the alkaline earth metals reacting with water? [3] 6. Of P 4, KF, C 6 H 6, and Br 2, which substance most likely has ionic bonding? Explain your thinking. [2] 7. The lower the density of a gas compared to the density of air, the more lifting power it gives in blimps. After examining the table, explain which gas you would use to inflate a blimp taking into account both lifting power and safety. [2] Gas Density at room temperature (g/cm 3 ) Combustibility hydrogen (H 2 ) high helium (He) none methane (CH 4 ) high carbon dioxide (CO 2 ) low air low 8. Create a flow chart of the categories that species at risk move through from normal populations to extinction. [3] 9. Summarize why introducing non-native species can be detrimental to an existing ecosystem. [2] Page 7

8 10. How much does it cost to operate a dishwasher one hour a day for 2 weeks if it uses 450 W. The cost for electricity is $ 0.12 /kwh. Show a full solution. [4] 11. How much current will be running through a bulb that has a resistance of 4 Ω and is provided with 12 V. Show a full solution. [3] 12. Sketch a circuit diagram showing a two-cell battery, an open switch, and two lamps connected in parallel. [3] 13. What does the red shift tell us about distant galaxies? [2] 14. Why is it that some stars set during the night, or disappear from view and other stars do not set? Explain what causes stars to set. [2] 15. Which do you think is more convenient for measuring distances in the Solar System, kilometres or astronomical units (AU)? Explain. Page 8

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