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Year 8 Revision Questions Chemistry Barnard Castle School 1 1. The drawings show six objects made from different materials. not to scale (a) Fill the gaps in the sentences below. The objects are made from materials that are all types of ........................... 1 mark All the materials are good conductors of electricity and ............................... 1 mark (b) From the drawings above give one object that could rust. ...................................................................................................................... 1 mark (c) The drawing below shows part of an electric cable and a plug. (i) What material could be put around the wires to insulate them? ............................................................................................................. 1 mark (ii) Why is this insulating material needed? ............................................................................................................. 1 mark Barnard Castle School 2 (d) Which pair of objects is attracted to a magnet? Tick the correct box. 1 mark maximum 6 marks 2. The list below shows properties that different elements can have. magnetic can be compressed very high melting point very low melting point good conductor of heat poor conductor of heat good conductor of electricity poor conductor of electricity (a) Which two properties from the list above make aluminium suitable for saucepans? 1. ................................................................................................................. 2. ................................................................................................................. 2 marks (b) Which property in the list above explains why: (i) copper is used in the cable of a television? ............................................................................................................. 1 mark (ii) a lot of oxygen gas can be pumped into a very small container? ............................................................................................................. 1 mark Barnard Castle School Maximum 4 marks 3 3. (a) The drawings below show three objects made from copper. Draw a line from each object to the reason for using copper for that object. Draw only three lines. object made from copper reason for using copper It does not rust. base of a saucepan It is a good conductor of electricity. coin It is a good conductor of heat. wires in a cable It is not magnetic. 3 marks Barnard Castle School 4 (b) Brass is a mixture of copper and zinc. Some keys are made from brass Why is brass more suitable than copper for a key? Tick the two correct boxes. Brass does not bend as easily as copper. Brass is a paler colour than copper. Brass is harder than copper. Brass is not as shiny as copper. Brass is not such a good conductor of electricity as copper. Brass is not such a good conductor of heat as copper. 2 marks (c) Zinc melts at 420ºC. Copper melts at 1085ºC. A scientist heated a mixture of pieces of zinc and pieces of copper to 600ºC in a dish. What would be in the dish at 600ºC? liquid zinc and liquid copper liquid zinc and solid copper solid zinc and liquid copper solid zinc and solid copper 1 mark maximum 6 marks Barnard Castle School 5 4. Part of the reactivity series of metals is shown below. most reactive potassium sodium magnesium aluminium iron lead least reactive (a) copper Dan added a piece of magnesium to a solution of copper sulphate. A displacement reaction took place. The word equation for the reaction is shown below. magnesium + copper sulphate magnesium sulphate + copper Why is this called a displacement reaction? ...................................................................................................................... ...................................................................................................................... 1 mark (b) Look at each pair of chemicals in the table below. Use the reactivity series to predict whether a displacement reaction would take place. Write yes or no in the second column and give the reason for your decision. pairs of chemicals Does a displacement reaction take place? yes or no reason iron + sodium chloride magnesium + lead nitrate 2 marks Barnard Castle School 6 (c) Dan wanted to find out where zinc should be placed in the reactivity series. (i) What tests should Dan do to find the correct position of zinc in the reactivity series? ............................................................................................................. ............................................................................................................. ............................................................................................................. 1 mark (ii) How would Dan use his test results to decide where to put zinc in the reactivity series? ............................................................................................................. ............................................................................................................. ............................................................................................................. 1 mark maximum 5 marks 5. (a) George used the apparatus below to find out what substances are produced when methanol burns. As the methanol burned, two different gases were produced. (i) One of these gases condensed in the U-tube to give a colourless liquid. Give the name of this liquid. ........................................................ 1 mark (ii) The other gas turned the lime water cloudy. Give the name of this gas. ........................................................ 1 mark Barnard Castle School 7 (b) Methanol is sometimes used in antifreeze. It can be added to water in car windscreen wash-bottles to prevent the water from freezing in cold conditions. (i) The label on the bottle of antifreeze has two hazard warning symbols. What two precautions would you need to take when using this antifreeze? 1. ......................................................................................................... ............................................................................................................. 2. ......................................................................................................... ............................................................................................................. 1 mark (ii) Water freezes at 0°C. The label on the bottle shows how the freezing point changes when different amounts of antifreeze are added to water. Terry put a mixture containing 10% antifreeze into the wash-bottle of his car. During the night the temperature dropped to –14°C. The wash-bottle burst. Explain why the wash-bottle burst. ............................................................................................................. ............................................................................................................. ............................................................................................................. ............................................................................................................. 2 marks Maximum 5 marks Barnard Castle School 8 6. (a) Sasha placed small samples of four different metals on a spotting tile. She added drops of calcium nitrate solution to each metal. spotting tile copper iron magnesium zinc Sasha repeated the experiment with: fresh samples of the four metals and copper nitrate solution fresh samples of the four metals and iron nitrate solution. Will a reaction take place when each of the metals is added to each of the solutions? Use the reactivity series below to help you. most reactive least reactive calcium magnesium aluminium zinc iron lead copper In the table below: place a tick, , to show that a reaction took place place a cross, X, to show that no reaction took place. Two have been done for you. metal salt solution copper iron magnesium zinc calcium nitrate copper nitrate iron nitrate X X 3 marks Barnard Castle School 9 (b) Three pairs of chemicals are listed below. A reaction only takes place with two of the pairs. Draw a line from each reaction to the correct result. Draw only three lines. pair of chemicals result calcium carbonate + hydrochloric acid no reaction magnesium + hydrochloric acid a chloride, carbon dioxide and water are formed copper + hydrochloric acid a chloride and hydrogen are formed 2 marks maximum 5 marks 7. The table shows the melting points and boiling points of four substances present in the air. (a) substance melting point, in °C boiling point, in °C carbon dioxide –78 –78 nitrogen –210 –196 oxygen –219 –183 water vapour 0 100 What happens to a piece of solid carbon dioxide if it is heated from –100°C to –78°C? ..................................................................................................................... ..................................................................................................................... 1 mark Barnard Castle School 10 (b) ‘Liquid air’ can be formed from air in a heat exchanger. As the air passes through, thermal energy is transferred from the air to the surroundings. This is shown in the flow diagram below. thermal energy thermal energy separator heat exchanger water (i) carbon dioxide 'liquid air' (a mixture of liquid oxygen and liquid nitrogen) Suggest a likely temperature for the ‘liquid air’ that leaves the heat exchanger. ................°C 1 mark (ii) Use the information in the table to explain why carbon dioxide and water vapour need to be removed from the air before it is pumped through pipes to the heat exchanger. State the consequences of not removing these two gases. ............................................................................................................. ............................................................................................................. ............................................................................................................. 2 marks (c) The ‘liquid air’ is a mixture of liquid nitrogen and liquid oxygen. Use the information in the table to suggest how liquid oxygen could be obtained from the mixture. ..................................................................................................................... 1 mark (d) A room measures 4 m x 3 m x 2.5 m. (i) The density of air is approximately 1.2 kg/m3. What is the approximate mass of air in the room? Give the unit. ............................................................................................................. ............................................................................................................. 2 marks Barnard Castle School 11 (ii) If the air in the room is cooled to a low enough temperature, it will change from a gas to a liquid. The density of ‘liquid air’ is 1125 kg/m3. What volume of ‘liquid air’ would the air in the room produce? Give the unit. ............................................................................................................. 1 mark (iii) How does the distance between the particles in atmospheric air compare to the size of the particles themselves? ............................................................................................................. 1 mark Maximum 9 marks 8. A teacher set up the following apparatus to separate the chemicals in cigarette smoke. The chemicals pass through the apparatus in the direction of the arrows. burning cigarette cotton wool ice cubes A (a) lime water water collects here B C In A, a brown sticky substance collected on the cotton wool. This substance causes lung cancer. Give the name of the brown substance. .............................................. 1 mark (b) As the cigarette burned, water vapour was produced and water collected in B. (i) Why were ice cubes needed in B? ............................................................................................................. ............................................................................................................. 1 mark Barnard Castle School 12 (ii) In the boxes below, draw the arrangement of particles of water vapour and particles of liquid water. Use a circle, O, to represent each particle. particles of water vapour particles of liquid water 2 marks (c) The lime water in C became cloudy. What gas turns lime water cloudy? ................................................ 1 mark Maximum 5 marks 9. A section of the periodic table of elements is shown below. H He (a) Li Be B C N O F Ne Na Mg Al Si P S Cl Ar Where in this section of the periodic table are the metals found? ...................................................................................................................... 1 mark (b) Sodium chloride is formed when sodium and chlorine combine together in a chemical reaction. Write the symbols for sodium and chlorine. sodium ………………………………….. chlorine ………………………………….. 2 marks (c) The formula for a substance is MgS. What is the name of this substance? ...................................................................................................................... 1 mark Barnard Castle School 13 (d) Give the name of one element in the table above which is a gas at room temperature and in which the atoms are joined together in molecules. ...................................................................................................................... 1 mark Maximum 5 marks 10. (a) Complete the word equation below for the reaction between calcium carbonate and hydrochloric acid. calcium carbonate hydrochloric acid .......... .......... .......... ..... carbon dioxide water 1 mark Limestone is mainly calcium carbonate. It is weathered by acids in the air or in soil. (b) In June 1990, a Year 9 class planned a long-term investigation into the chemical weathering of limestone by acids in soil. They put limestone chippings of similar size in three nylon mesh bags. They buried the bags outside in soils of different pH. (i) Chemical weathering took place in sample A, and the mass of the sample decreased. Give the reason for the decrease in mass. Use the word equation above to help you. ............................................................................................................. ............................................................................................................. 1 mark (ii) The pupils predicted that chemical weathering would not take place in samples B and C. Give the reason for their prediction. ............................................................................................................. ............................................................................................................. 1 mark Barnard Castle School 14 (iii) Some chemical weathering did take place in samples B and C. What could have changed the conditions in these soils to cause weathering to take place? ............................................................................................................. 1 mark (c) The table shows how the mass of each sample changed between the years 1990 and 2000. mass, in g year sample A, at pH 5 sample B, at pH 7 sample C, at pH 8 1990 1000 1000 1000 1995 980 992 997 2000 960 984 995 In 2000, a year 9 class buried another identical 1000 g sample of limestone chippings in soil of pH 6. (i) Use the results in the table to predict an approximate value for the mass of this sample in 2010. ................. g 1 mark (ii) Why is it not possible to be certain what the mass of this sample will be in 2010? ............................................................................................................. ............................................................................................................. 1 mark Maximum 6 marks Barnard Castle School 15 11. Paul had four substances: citric acid copper sulphate indigestion tablet sugar He dissolved 1 g of each substance in 20 cm3 of distilled water. He used universal indicator to find the pH of each solution. (a) (i) Sugar solution does not change the colour of green universal indicator. What does this tell you about sugar solution? Tick the correct box. It is an acid. It is an alkali. It is neutral. It is sweet. 1 mark (ii) Suggest the pH of citric acid. ............ 1 mark (iii) Indigestion tablets neutralise acid in the stomach. What does this tell you about indigestion tablets? ............................................................................................................... 1 mark (b) Complete the flow chart below with the names of the substances in the boxes. citric acid Barnard Castle School copper sulphate indigestion tablet sugar 16 Does the substance dissolve in water to form a blue solution? yes no Does it turn universal indicator red? yes no Does it turn universal indicator blue? yes no 3 marks maximum 6 marks Barnard Castle School 17 12. A science teacher showed her class three experiments, A, B and C. The experiments and the word equations for the reactions that took place are shown below. All the experiments were done in a fume cupboard. experiment A calcium carbonate calcium oxide forms in the test tube 0 1 2 3 4 5 calcium carbonate is heated word equation 0 1 2 3 4 5 carbon dioxide is collected here calcium carbonate calcium oxide + carbon dioxide experiment B iron filings and sulphur are heated together word equation iron + sulphur iron sulphide experiment C copper hot copper is added to chlorine word equation Barnard Castle School piece of copper covered with brownish solid chlorine copper + chlorine ________________________ 18 (a) From the substances in experiments A, B and C, above, give the name of: (i) one metallic element; ............................................................. 1 mark (ii) one non-metallic element; ............................................................. 1 mark (iii) two compounds. ................................................... and ................................................... 1 mark (b) In experiment B, the iron filings weighed 2.0 g at the beginning of the experiment and the iron sulphide produced weighed 2.8 g. Explain this increase in mass. ......................................................................................................................... ......................................................................................................................... 1 mark (c) Complete the word equation for the chemical reaction in experiment C. copper + chlorine ............................................................. 1 mark maximum 5 marks Barnard Castle School 19 13. The diagram shows part of the Periodic Table. period 0 1 H I II III IV V VI VII He 2 Li Be B C N O F Ne 3 Na Mg Al Si P S Cl Ar Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 4 5 (a) K Ca Sc Ti V Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Rb Sr Sn Sb Te I Xe Calcium burns brightly in oxygen, forming calcium oxide (CaO). Calcium oxide reacts with water, forming a compound with the formula Ca(OH)2. (i) Give the name of the compound with the formula Ca(OH)2. ………………………………………………………………………………… 1 mark (ii) The compound, Ca(OH)2, is slightly soluble in water. Would you expect this solution to be acidic, alkaline or neutral? …………………………………… 1 mark (b) The table below gives information about four compounds. The molecules of each compound contain an atom of hydrogen and an atom of an element from group VII of the Periodic Table. The amount of energy needed to pull the two atoms apart is called the bond strength. compound name formula hydrogen HF fluride hydrogen HCl chloride hydrogen HBr bromide hydrogen HI iodide Barnard Castle School bond strength in Kj/mol action of heat on the compound 570 stable 432 fairly stable 366 some bromine formed 298 20 14. Use the valency information you have been given to work out he chemical formulae of the compounds listed (i) to (vi). I. II. Sodium bromide Potassium hydroxide III. Silver chloride IV. Barium chloride V. VI. Magnesium hydroxide Iron(III) oxide Barnard Castle School 21