Q. Scientists study the atmosphere on planets and moons in the Solar System to understand how the Earth s atmosphere has changed. (a) Millions of years ago the Earth s atmosphere was probably just like that of Mars today. The table shows data about the atmospheres of Mars and Earth as they are now. Mars Earth nitrogen 3% nitrogen 78% oxygen trace oxygen 2% water trace water trace carbon dioxide 95% carbon dioxide trace Average surface temperature 23 C Average surface temperature 5 C Suggest what has caused the main gases in the Earth s atmosphere of millions of years ago to change to the present-day atmosphere............. (2) (b) Titan is the largest moon of the planet Saturn. It has an atmosphere that, like the Earth s, contains mainly nitrogen. Methane is the other main gas. Main gases in Titan s atmosphere Percentage (%) Boiling point in C Nitrogen 95 96 Methane 5 64 Average surface temperature 78 C When it rains on Titan, it rains methane! Explain why.......... (2) Page of 7
(c) Ultraviolet radiation from the Sun produces simple alkenes, such as ethene and propene, from methane in Titan s atmosphere. (i) Draw the structure of propene, C 3 H 6, to show the covalent bonds. () (ii) Explain how propene molecules form a polymer. You should name the polymer formed....... (3) (Total 8 marks) Q2. Sulfur is a non-metal. Sulfur burns in the air to produce sulfur dioxide, SO 2 (a) Why is it important that sulfur dioxide is not released into the atmosphere? Tick ( ) one box. Sulfur dioxide causes acid rain. Sulfur dioxide causes global dimming. Sulfur dioxide causes global warming. () Page 2 of 7
(b) Sulfur dioxide dissolves in water. What colour is universal indicator in a solution of sulfur dioxide? Give a reason for your answer. (2) (c) Sulfur dioxide is a gas at room temperature. The bonding in sulfur dioxide is covalent. Explain, in terms of its structure and bonding, why sulfur dioxide has a low boiling point. (3) Page 3 of 7
(d) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. Sulfur dioxide is produced when fossil fuels are burned. It is important that sulfur dioxide is not released into the atmosphere. Three of the methods used to remove sulfur dioxide from gases produced when fossil fuels are burned are: wet gas desulfurisation (W) dry gas desulfurisation (D) seawater gas desulfurisation (S). Information about the three methods is given in the bar chart and in Table and Table 2. Method of removing sulfur dioxide Table Method Material used How material is obtained W Calcium carbonate, CaCO 3 Quarrying D Calcium oxide, CaO Thermal decomposition of calcium carbonate: CaCO 3 CaO + CO 2 S Seawater From the sea Table 2 Method W D S What is done with waste material Solid waste is sold for use in buildings. Carbon dioxide is released into the atmosphere. Solid waste is sent to landfill. Liquid waste is returned to the sea. Page 4 of 7
Evaluate the three methods of removing sulfur dioxide from waste gases. Compare the three methods and give a justified conclusion. (6) (Total 2 marks) Page 5 of 7
Q3. The Earth has a layered structure and is surrounded by an atmosphere. (a) The diagram shows the layers of the Earth. Complete the labels on the diagram. (2) Page 6 of 7
(b) The data in the table shows the percentages of the gases in the Earth s atmosphere. Name of gas Percentage (%) of gas Nitrogen 78 Oxygen 2 Other gases Present the data in the table on the grid below. (3) Page 7 of 7
(c) Millions of years ago a large meteorite hit the Earth. The meteorite heated limestone in the Earth s crust to a very high temperature. The heat caused calcium carbonate in the limestone to release large amounts of carbon dioxide. Draw a ring round the correct answer to complete each sentence. decomposed. (i) Carbon dioxide was released because the calcium carbonate was evaporated. reduced. () acid rain. (ii) More carbon dioxide in the Earth s atmosphere causes global dimming. global warming. () (Total 7 marks) Page 8 of 7
Q4. In 95 Wegener proposed his idea of continental drift. About 50 years later the theory of plate tectonics was developed and this confirmed his idea. (a) Give one reason why Wegener s idea was not accepted in 95. () (b) The theory of plate tectonics is used to explain why earthquakes occur. Explain how earthquakes occur. (2) (c) Suggest why it is difficult to predict when an earthquake will occur. () (Total 4 marks) Page 9 of 7
Q5. Evidence shows that the Earth formed from a molten ball of rocks and minerals. Before 900 many scientists thought that the Earth s mountains and continents formed in fixed positions when the molten ball of rocks and minerals cooled and wrinkled. (a) In 92 Alfred Wegener suggested his hypothesis of continental drift. The areas of rocks shown on Map contain fossils of the same type of animals. Today animals in Africa are different from animals in South America. Map Wegener suggested his hypthesis that all of the continents, including Africa and South America, had been joined together but then drifted slowly apart. Map 2 In 920 other scientists stated that all of the continents were in fixed positions, including Africa and South America, and that they had once been joined together by a land bridge. (i) Use the information to suggest two pieces of evidence that may have led Wegener to propose his hypothesis that continents move............. (2) (ii) Suggest why, in 920, other scientists thought that Wegener s hypothesis was wrong............. (2) Page 0 of 7
(b) In 962 scientists produced the theory of plate tectonics. The theory of plate tectonics supported Wegener s hypothesis that continents move. Tectonic plates move a few centimetres a year. Complete the sentences about what causes the movement of the Earth s tectonic plates. Deep inside the Earth... processes release large amounts of energy. These processes heat up the substances in the Earth s... producing convection currents. (2) (Total 6 marks) Page of 7
M. (a) any two from: asks for cause therefore no marks for just describing the change must link reason to a correct change in a gas carbon dioxide has decreased due to: accept idea of used to indicate a decrease plants / micro organisms / bacteria / vegetation / trees photosynthesis ignore respiration locked up in (sedimentary) rocks / carbonates / fossil fuels dissolved in oceans ignore volcanoes oxygen has increased due to: accept idea of given out / produced plants / bacteria / micro organisms / vegetation / trees photosynthesis ignore respiration nitrogen increased due to: accept idea of given out / produced ammonia reacted with oxygen bacteria / micro organisms ignore (increase in) use of fossil fuels / deforestation 2 (b) (because methane s) boiling point is greater than the average / surface temperature or Titan s (average / surface) temperature is below methane s boiling point ignore references to nitrogen or water any methane that evaporates will condense accept boils for evaporates accept cooling and produce rain for condensing (c) (i) bonds must be displayed correctly ignore bond angles Page 2 of 7
(ii) poly(propene) / polypropene / polypropylene do not allow polypropane any two from: double bonds open up / break / become single(*) propene molecules / monomers / they join / undergo addition polymerisation(*) form chains / long molecules(*) (*)correct chemical equation gains 2 marks ignore large using monomer incorrectly max 2 marks 2 [8] M2. (a) Sulfur dioxide causes acid rain. (b) red / orange / yellow do not accept any other colours (c) because sulfur dioxide (when in solution) is an acid (there are) weak forces (of attraction) do not accept any reference to covalent bonds breaking between the molecules do not accept any other particles (these) take little energy to overcome award third mark only if first mark given Page 3 of 7
(d) Marks awarded for this answer will be determined by the Quality of Communication (QC) as well as the standard of the scientific response. Examiners should also refer to the information on page 5 and apply a best-fit approach to the marking. 0 marks No relevant content Level ( 2 marks) A relevant comment is made about the data. Level 2 (3 4 marks) Relevant comparisons have been made, and an attempt made at a conclusion. Level 3 (5 6 marks) Relevant, detailed comparisons made and a justified conclusion given. examples of the points made in the response effectiveness W removes the most sulfur dioxide D removes the least sulfur dioxide material used Both W and D use calcium carbonate Calcium carbonate is obtained by quarrying which will create scars on landscape / destroy habitats D requires thermal decomposition, this requires energy D produces carbon dioxide which may cause global warming / climate change S uses sea water, this is readily available / cheap waste materials W product can be sold / is useful W makes carbon dioxide which may cause global warming / climate change D waste fill landfill sites S returned to sea / may pollute sea / easy to dispose of 6 [2] M3. (a) crust ignore Earth s core ignore inner and/or outer (b) bar chart all heights are correct accept correctly plotted points Page 4 of 7
all labels are correct for nitrogen, oxygen and other / argon (c) (i) decomposed (ii) global warming [7] M4. (a) no / insufficient evidence / proof / explanation accept there were other theories such as a land bridge / solid crust (b) (continental / tectonic) plates move any one from: (caused by) convection currents (in the mantle) (driven by) heat (energy) released by radioactive processes / decay sudden (movement) / vibrations (c) any one from: do not know / see / able to detect / measure what is happening below the Earth s crust ignore cannot measure movement of plates / unpredictable build up of pressure between plates is randomly released accept (movement) is random / no pattern [4] M5. (a) (i) the continents of South America and Africa would have fitted together like a jigsaw there are matching / similar rocks / fossils on the continents of South America and Africa Page 5 of 7
(ii) other scientists thought that continents are fixed / cannot float or Wegener had no evidence to prove that continents can move allow Wegener was not respected by other scientists / PhD in astronomy and that a land bridge could explain the matching / similar rocks / fossils on the continents of South America and Africa (b) radioactive mantle words must be in the order shown [6] Page 6 of 7
Page 7 of 7