oxford cambridge and rsa monday 15 may 2017 – morning...monday 15 may 2017 – morning as gce...
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Monday 15 May 2017 – MorningAS GCE SCIENCEG641/01 Remote Sensing and the Natural Environment
INSTRUCTIONS TO CANDIDATES• Write your name, centre number and candidate number in the boxes above. Please write
clearly and in capital letters.• Use black ink. HB pencil may be used for graphs and diagrams only.• Answer all the questions.• Read each question carefully. Make sure you know what you have to do before starting your
answer.• Write your answer to each question in the space provided. If additional space is required, you
should use the lined page(s) at the end of this booklet. The question number(s) must be clearly shown.
• Do not write in the barcodes.
INFORMATION FOR CANDIDATES• The number of marks is given in brackets [ ] at the end of each question or part question.• The total number of marks for this paper is 60.• You are advised to show all the steps in any calculations.• Where you see this icon you will be awarded marks for the quality of written
communication in your answer. This means, for example, you should:
• ensure that text is legible and that spelling, punctuation and grammar are accurate so that meaning is clear;
• organise information clearly and coherently, using specialist vocabulary when appropriate.• You may use an electronic calculator.• This document consists of 16 pages. Any blank pages are indicated.
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Candidates answer on the Question Paper.
OCR supplied materials:None
Other materials required:• Electronic calculator• Ruler (cm/mm)
Duration: 1 hour
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AS SCIENCE RELATIONSHIPS SHEET
pressure = force ÷ area
energy transferred = mass × specific heat capacity × temperature rise
density = mass ÷ volume
wavenumber = 1 / wavelength
speed = frequency × wavelength
energy = Planck constant × frequency
current = charge ÷ time
power = voltage × current
power loss = (current)2 × resistance
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BLANK PAGE
Question 1 begins on page 4
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Answer all the questions.
1 Sports drinks give athletes a quick energy boost.
(a) (i) Suggest the ingredient in these drinks that gives this energy boost.
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(ii) The energy is released during the process of aerobic respiration in cells.
Write the word equation for the overall reaction that occurs in aerobic respiration.
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(iii) Name the molecule produced during respiration that supplies the cells with an immediate source of energy.
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(b) The two stages of aerobic respiration take place at two sites within the cell.
Name these two sites and describe what happens at each site.
Site 1 ........................................................................................................................................
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(c) Some of the energy released by aerobic respiration will be used by the athlete for muscle cell contraction.
Suggest two other uses for this energy in a cell.
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(d) Another type of respiration is anaerobic respiration.
(i) State the condition in which anaerobic respiration occurs.
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(ii) State two differences between the processes of aerobic and anaerobic respiration.
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[Total: 12]
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2 In recent years, many people have started to grow plants on the roofs of buildings in cities, as shown in Fig. 2.1. These roofs are known as ‘green roofs’.
Fig. 2.1
(a) The plants on ‘green roofs’ remove carbon dioxide from the city air.
Suggest two different sources of carbon dioxide in a large city.
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(b) Describe how plants remove carbon dioxide from the air.
In your answer, include details of: • the reactants and products involved • the stages of the process • where in the plant cell the process occurs.
In your answer, you should use appropriate technical terms, spelled correctly.
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(c) Plants grow better if the soil in which they are grown is rich in nitrates.
State one use of nitrates by a plant.
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(d) Nitrates are involved in the nitrogen cycle.
Fig. 2.2 shows some of the pathways and stages in the nitrogen cycle.
nitrogen in the atmosphere
nitrates in the soil
nitrogen compoundsin plants + animals
ammonia
A C
B
lightning
manufactureof fertiliser
Fig. 2.2
Different types of bacteria are needed for stages A, B and C.
Select the type of bacteria from the box below to fill in the table.
assimilating denitrifying nitrifying nitrogen-fixing pathogenic
Stage Type of bacteria
A
B
C
[3]
(e) The use of nitrogen-based fertilisers is now a very important part of the nitrogen cycle. The fertilisers replace nitrates lost from the soil.
Describe one way the nitrates can be lost from the soil.
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(f) The Haber process converts nitrogen and hydrogen into ammonia. Nitrogen-based fertilisers are made from ammonia.
The chemical equation for the reaction is
N2 + 3H2 2NH3
Suggest a suitable source of nitrogen for the Haber process.
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(g) The yield of ammonia in the Haber process is a measure of the percentage of the reactants that are converted into ammonia.
Fig. 2.3 shows how the yield of ammonia varies with pressure at different temperatures.
350 °C
400 °C
450 °C
500 °C
550 °C
(0)0
10
20
30
40
50
60
70
80
90
100
(100) (200) (300) (400)
pressure / atmospheres
yield ofammonia / %
Fig. 2.3
(i) Use the graph to find the yield of ammonia at 200 atmospheres and 500 °C.
Yield = ...................................................... % [1]
(ii) Suggest two changes to the conditions that will increase this yield of ammonia.
Use the graph to help you.
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[Total: 17]
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3 Fig. 3.1 shows a visible light image from a satellite. It shows cyclone Irina over the Indian Ocean.
Fig. 3.1
(a) The information needed to produce the image is gathered using a sensing device known as a charge-coupled device (CCD).
(i) Describe how the CCD gathers this information and how it uses the information to create the image.
In your answer, you should use appropriate technical terms, spelled correctly.
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(ii) The quality of a visible light image can be limited by scattering.
Describe how two different components of the atmosphere scatter different colours of visible light.
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(b) Scientists monitoring the weather often find thermal infrared images more useful than visible light images.
(i) Give two advantages of thermal infrared images compared with visible light images.
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(ii) State one way a thermal infrared wave differs from a visible light wave.
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(c) Thermal infrared images can be displayed as digital grey-scale images or false colour images.
Explain why false colour images are easier to interpret than digital grey-scale images.
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[Total: 11]
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4 An X-ray is an electromagnetic wave.
(a) Calculate the wavelength of an X-ray with a frequency of 2.3 × 1017 Hz.
Speed of light = 3.0 × 108 ms–1
Show your working and give your answer in standard form to 2 significant figures.
Wavelength = ........................................ unit .......... [4]
(b) X-ray diffraction can be used to work out the arrangement of atoms in a crystal.
(i) State what is meant by the term diffraction.
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(ii) The X-ray wave is diffracted as it passes through a crystal.
What does this tell you about the distance between the atoms in this crystal?
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(c) Scientists working with X-rays need to take precautions to reduce the risk of developing cancer.
Explain how X-rays may cause cancer.
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[Total: 10]
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5 Fig. 5.1 shows the distribution of some forest biomes on Earth.
Boreal
Temperate
Tropical
Key
Fig. 5.1
Some data about these forest types are given in Table 5.1.
Forest biome Mean productivity/kJ m–2yr–1
Boreal 15 000
Temperate 25 000
Tropical 38 000
Table 5.1
(a) State what is meant by the productivity of a forest biome.
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(b) Suggest two reasons why the productivity of the boreal forest is much lower than the productivity of the tropical forest.
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(c) Decomposers play an important role in the food web of a forest.
(i) Name one type of decomposer ..................................................................................... [1]
(ii) Explain the role of the decomposers and how they benefit the forest ecosystem.
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(d) Forests used to cover about 65% of the Earth’s land surface. This percentage has now decreased to about 25%.
Suggest reasons for this decrease and explain why we should be concerned about it.
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[Total: 10]
END OF QUESTION PAPER
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