NATIONAL 4 CHEMISTRY

Transcription

1 Farr High School NATIONAL 4 CHEMISTRY Unit 3 Chemistry in Society Question Booklet 1

2 Properties of Metals and Alloys 1. The grid below shows the names of some metals. You can use your data book to help you to find the answers to the questions below. lithium gold iron zinc calcium magnesium a) Identify the metal found uncombined in the Earth s crust. b) Identify the metal produced in a blast furnace. c) Identify the most reactive metal. 2. Medical instruments can be made from a mixture of metals containing 76% titanium, 4% zirconium and the rest is other metals. a) What name is given to a mixture of metals? b) Copy and label the pie chart to show the name and percentage for each part of the mixture. 2

3 3. What is an ore? 4. Why was gold one of the first metals to be used by man? 5. Name two metals which can be extracted from their ores by heat alone. 6. Name three metals, other than those in 8, which can be extracted from their ores by heating with carbon. 7. Name two metals which must be extracted from their ores by other means. 8. How can the ores of metals higher than zinc in the electrochemical series be extracted? 9. A teacher demonstrated the following experiment. a) The Universal indicator changed colour from green to purple. What does this tell you about the solution? b) Why is lithium stored under oil? 10. Choose which metal from the list matches each statement below. copper tin iron silver sodium a) A metal which is used in jewellery because it is shiny and unreactive. b) A metal which rusts if it is left out in damp air. c) A metal that can be used as a coating on cans because it is less reactive than iron. d) A metal which is soft and can be cut with a knife, and which reacts easily with air and water. e) A metal which is used for coins and pipes because it hardly reacts with air or water. 3

4 11. Naveed carried out an experiment to investigate the reaction of 3 metals with sulphuric acid. a) Place the metals in order of reactivity (most reactive first). b) Name the gas that would be released in this reaction. c) Explain how you would test this gas to show what it is. d) Explain what you would see if Naveed used more concentrated sulphuric acid. 12. The Falkirk Wheel is a steel structure which carries boats from one level of the canal to another. a) The Falkirk Wheel is painted to prevent rusting. How does painting prevent rusting? b) Suggest another method to prevent rusting. c) Steel is an alloy. What does this term mean? d) Name another alloy. e) The table gives information on some steel alloys. Carbon present in steel alloys (%) Hardness (Units) Predict the hardness of a steel containing 0.6% carbon f) Suggest one advantage of using steel compared to iron. 4

5 13. A student set up this experiment with clean nails in two dishes containing ferroxyl indicator to investigate rusting. The diagram below shows the results of the experiment after 1 day. a) Write the symbol for the iron ion which turns ferroxyl indicator blue. b) Explain why the magnesium attached to the iron nail prevents rusting. 14. Different methods can be used to prevent steel from rusting. a) How does tin-plating prevent steel from rusting? b) Name a metal which can be used to provide sacrificial protection to steel. You may wish to use your data book to help you. 15. A teacher demonstrated the experiment below. Her results are shown below. Metal Zinc Copper Silver Observation Glowed brightly Dull red glow No reaction a) Predict what would happen if magnesium was used in this reaction. You may wish to use your data book to help you. b) In a different experiment powdered zinc was used instead of a metal strip. How would this affect the speed of the reaction? c) Silver is found uncombined in the earth s crust. Name another metal that is found uncombined in the earth s crust. You may wish to use your data book to help you. 5

6 16. Coating iron prevents rusting. tin paint oil zinc plastic magnesium a) Identify the coating used to galvanise iron. b) Identify the coating, which if scratched, would cause the iron to rust fastest. 17. Steel can be used to make storage tanks for diesel. One method of protecting the tanks from rusting is to connect magnesium to them. a) Name two substances that must be present for steel to rust. b) Name the type of protection offered by the magnesium. c) Suggest another method of protecting steel from rusting. 6

7 Electrochemistry 1. a) What produces the current in a battery? b) Why do batteries go flat? c) Give one advantage of using batteries over mains electricity. d) Besides going flat, give one disadvantage of using batteries over mains electricity. 2. A battery is a number of cells joined together. a) Give one advantage of using a battery compared with mains electricity b) Why does a battery stop producing electricity after a while? c) A simple cell was set up using a lemon as shown below. Use your data book to help you with the next two questions. i) Which direction would the electrons flow in? ii) Would the voltage be higher or lower if copper was used instead of nickel? 3. A student investigated how different metals affect the voltage in a simple cell. The results are shown in the table. Metal A Voltage/V Magnesium 2.7 Tin 0.5 a) The student set up another cell using iron and copper. Use your data book p7 to work out the voltage produced by this cell. b) Suggest one factor the student would have kept the same to make a fair comparison. 7

8 4. A student set up the cell shown. a) Which direction will the electrons flow in? b) Name a metal which could be used to replace the iron to give a smaller voltage. You may wish to use p7 of the data book to help you. c) What is the purpose of the ion bridge? 5. The diagram below shows a cell. a) Name the type of charged particle that flow through the wires. b) The voltage produced by the cell is 1.15V. Name a metal that could replace zinc to give a higher voltage. You may wish to use p7 of the data book to help you. c) Scientists at the University of St Andrews have developed a type of battery. It has the advantage of being able to store up to 10 times more energy than some other types of battery. Suggest another advantage of using this type of battery. 6. What name is given to the liquid inside a battery that completes the circuit by carrying the current between the metal plates? 8

9 Materials 1. PVC Production In the manufacture of PVC, ethylene and chlorine are passed through a catalyst chamber producing ethylene dichloride. The ethylene dichloride is then cracked to produce vinyl chloride which undergoes polymerisation to form the plastic poly(vinyl chloride), PVC. a) Use this information to label parts (i) to (iv) in the flow diagram. b) The systematic name for vinyl chloride is chloroethene. i) Show the structural formula for chloroethene. ii) What would be the systematic name for the polymer formed from chloroethene? 9

10 2. What is a polymer? 3. What is the name of the monomer used to make a polyvinylchloride b polybutene? 4. What is the name of the polymer made from a tetrafluoroethene b styrene? 5. What does non-biodegradable mean? 6. Write down one advantage of plastics being non-biodegradable. 7. Write down one disadvantage of plastics being non-biodegradable. 8. Plastics have many uses. Perspex is used to make advertising signs. Artificial limbs can be made from PVC. Polythene can be used to make carrier bags and egg cartons can be made from polystyrene. a) Present this information as a table with suitable headings. b) Scientists have produced a plastic which is biodegradable. What does this word mean? c) PVC softens when heated and can be easily shaped. What name is given to this type of plastic? d) Name the monomer that is used to make poly(styrene). e) Name the type of chemical reaction that is used to make poly(styrene) 9. Here is an aluminium pan heating on a camping stove. a) The aluminium pot is strong, light and does not melt when heated. Name another property of aluminium which makes it useful for cooking pots. b) The plastic handle also does not melt when heated. What name is given to this type of plastic? 10. Polystyrene is a plastic used in packaging. Scientists have found that starch, made from sources such as barley, can be used to make a packaging material with similar properties to polystyrene. Suggest one advantage of this material compared to polystyrene. 10

11 11. The plastic poly(propene) (PPE) has many uses. a) Name the monomer used to make poly(propene). b) Poly(propene) is non-biodegradable. Suggest why this might be an advantage. c) Poly(propene) can be used as a fibre in clothing. Laura set up the apparatus below to investigate the strength of different fibres. Her results table is shown here. i) How does the strength of the natural fibres compare to the strength of the synthetic fibres? ii) She tested Fibre X and found it broke at 300g. Predict whether this fibre is natural or synthetic. 12. Some supermarkets no longer supply free polythene bags because they are non-biodegradable and can cause environmental problems. a) What does non-biodegradable mean? b) Draw a section of polythene, showing 3 monomer units joined together. 11

12 Fertilisers 1. Nitric acid can be used to make fertilisers. Explain why there has been a major increase in the use of fertilisers over the last 100 years. 2. Ammonium nitrate is a synthetic fertiliser. It contains nitrogen which is essential for plant growth. a) What is meant by the term synthetic? b) Name another essential element supplied by fertilisers. c) When ammonium nitrate is heated with calcium hydroxide, a colourless gas is produced. The gas turns damp ph paper blue. Name the colourless gas. d) Some compounds containing essential elements are unsuitable for use as fertilisers. Suggest a reason for this. e) Certain plants contain bacteria which can convert nitrogen from the air into nitrogen compounds. Which part of the plant contains these bacteria? 3. A teacher demonstrated an experiment to show how nitrogen dioxide is formed in a petrol engine. a) Name the two gases that react to form nitrogen dioxide. b) Nitrogen dioxide can be formed naturally in air. What provides the high voltage spark for this reaction? c) Nitrogen dioxide dissolves in water. Suggest a ph value for the resulting solution. 12

13 4. Ammonia can be used in industry to make nitric acid. a) Name this industrial process. b) The reaction is exothermic. What does this term mean? c) Which two elements are combined to form ammonia? d) Name the industrial process used to make ammonia from its elements. 5. The graph shows how the level of nitrates in the soil of a farmers field varies in a particular year. a) Suggest why the level of nitrates increased in April. b) Suggest why the level of nitrates decreased from April to August. c) During periods of heavy rain, nitrates from the soil are washed into rivers. What effect does this have on the rivers? 6. a) Name the three elements essential for healthy plant growth. b) Why do farmers have to use synthetic fertilisers? c) Why should synthetic fertilisers be soluble? d) Name a natural fertiliser used by farmers. 7. Present this information on the ELEMENTS IN THE SOIL in a suitable graphical form. Element Percentage Element Percentage Oxygen 48 Silicon 25 Aluminium 10 Iron 5 Calcium 4 Sodium 3 Potassium 2.5 Magnesium 2.5 Others

14 Nuclear Chemistry 1. Nuclear fusion takes place in the stars. a) What is meant by nuclear fusion? b) Why is it important? 2. The radiation that is all around us is known as background radiation. Give a source of a) artificial radiation b) natural radiation 3. Name the instrument used to count nuclear radiation. 14

15 Chemical Analysis 1. The grid shows the formulae for some compounds. CuCl 2 Na 2 O LiF SO 2 BaF 2 SiCl 4 Use the table on p4 of your data book to answer the next two questions. a) Which compound would give a red flame colour? b) Which compound would give a green flame colour? c) Is flame testing an example of qualitative or quantitative analysis? 2. A student measured the ph of malt vinegar and some other substances. Her results are shown in the table. a) Describe how the student would use universal indicator or ph paper to test the substances. b) Malt vinegar is a mixture of ethanoic acid and water. Suggest a ph value for malt vinegar. 15

16 3. Many ionic compounds are coloured. Using the information in the table, state the colour of a) the chloride ion b) the dichromate ion 4. When aluminium iodide solution and lead nitrate solution are mixed together a chemical reaction takes place. a) Name the solution formed in this reaction. Use your data book p5 to help you. b) Explain how you would remove the solid formed in the reaction. 16