National 5 Unit Hydrocarbons 2. Consumer Products 3. Energy from Fuels. Homework Booklet

Transcription

1 National 5 Unit 2 1. Hydrocarbons 2. Consumer Products 3. Energy from Fuels Homework Booklet 1

2 Exercise 1 Revision Cracking 1. a) Paraffin a hydrocarbon. What are the products of burning paraffin in a plentiful supply of oxygen? b) Paraffin has no immediate effect on bromine water. What does this suggest about the structure of this hydrocarbon? c) A pupil carried out the following experiment. (i) (ii) (iii) What is the name of this chemical reaction? The product gas collected in the upturned test-tube rapidly decolourises bromine water. What does this suggest about this gas? During this reaction the following change occurs C8H18 C6H14 + X Name hydrocarbon X 2. Cracking long-chained hydrocarbons produces smaller, more useful molecules. One of the reactions taking place is: Draw the structural formula of octane. Write the molecular formula for X. (c) X is an alkene. What useful products are made from alkenes? 2

3 Homework 2 Hydrocarbons 1. Hydrocarbons contain hydrogen and carbon only. Identify the two hydrocarbons which are alkanes. 2. The names of some hydrocarbons are shown. Identify the hydrocarbon with five carbon atoms in each molecule. Identify the hydrocarbon which is the first member of the alkene family 3. Hydrocarbons are compounds that contain hydrogen and carbon only. Identify the molecular formula for pentane Identify the two molecular formulae which represent alkenes. 3

4 4. The grid shows the names of some hydrocarbons. Identify the hydrocarbon with six carbon atoms in the molecule. Identify the two hydrocarbons which are alkenes. 5. The names of some hydrocarbons are shown in the grid. Identify the two alkanes. Identify the hydrocarbon with molecular formula C4H8. 6. The formulae for some hydrocarbons are shown in the grid. Identify the two hydrocarbons which could be produced when propane (C3H8) is cracked. Identify the hydrocarbon with the highest boiling point. You may wish to use page 6 of the data book to help you. 4

5 7. Candle wax contains hydrocarbons. Name the elements present in a hydrocarbon. A student carried out the following experiment. (i) (ii) Which gas is used up when the candle burns? In the experiment a gas was produced which turned the lime water milky. Name the gas produced? 8. Explain what is meant by A saturated hydrocarbon An unsaturated hydrocarbon (c) Draw the full structural formula and shortened structural formula for ethene, butene and hexene. (d) Name the following alkenes: (i) (ii) 5

6 Exercise 3 - Hydrocarbons 1. Which of the following could be the molecular formula of a cycloalkane? A B C D C7H16 C7H14 C7H12 C7H10 2. Which of the following compounds fits the general formula, CnH2n, and will rapidly decolourise bromine solution? A B C D Pentane Pentene Cyclopentane Cyclopentene 3. Which of the following hydrocarbons does not belong to the same homologous series as the others? A B C D CH4 C3H6 C4H8 C6H12 4. The first three members of the alkyne homologous series are: What is the general formula for this homologous series? A B C D CnHn CnHn+1 CnHn+2 CnH2n-2 6

7 5. Which of the following compounds belongs to the same homologous series as the compound with molecular formula C3H8? 6. Which of the following compounds has an isomer? 7

8 7. Two isomers of butene are; Which of the following structures represents a third isomer of butene? 8. Which of the following is an isomer of heptane? 8

9 9. Which compound is an isomer of the one shown above? 10. The name of the above compound is A B C D Pent-2-ene But-2-ene Pent-3-ene But-3-ene 9

10 11. The name of the above compound is A B C D 1,1 dimethylpropane 2 ethylpropane 2 methylbutane 3 methylbutane 12. Which line in the table correctly identifies the Process X and the Compound Y? 10

11 Exercise 4 Hydrocarbons 1. The structure of an alkane is shown below. (c) Name this alkane. Draw the shortened structural formula for this alkane. The alkanes are said to be members of a homologous series. What is meant by a homologous series? 2. A student completed an experiment Testing for Unsaturation. Results from the experiment are shown below. Complete the table. Care had to be taken when using bromine solution. Give a safety precaution other than eye protection, which should be taken when completing this experiment. (c) Draw the structure of hydrocarbon B. (d) Draw a possible branched structure for hydrocarbon A. 3. The diagram shows how paraffin, C12H26, can be cracked. (c) Name the catalyst used in cracking. Explain why the delivery tube must be removed from the bromine solution before heating is stopped. One of the reactions taking place when paraffin is cracked is 11

12 (d) (i) Identify molecule X. (ii) Describe what would be seen when X is added to bromine solution. One other reaction that is taking place is CH3CH2CHCH2 + Br2 CH3CH2CHBrCH2Br What name is given to this type of chemical reaction? 4. Gases can be liquefied by increasing pressure, but above a certain temperature it is not possible to do this. This temperature is known as the critical temperature. The critical temperatures of the alkanes are shown below Describe the trend in critical temperatures for the straight-chained alkanes. Predict the critical temperature of the alkane below. (c) Give the systematic name of this branched alkane. 5. Iodine can react with propene in the following way. (c) (d) Name the homologous series to which propene belongs. Draw the shortened structural formula of propene. Name the type of reaction taking place when iodine reacts with propene. Draw an isomer of propene which is a member of a different homologous series. 12

13 Exercise 1 Revision 1. The fermentation of glucose is catalysed by the enzyme zymase. C6H12O6(aq) C2H5OH(aq) + CO2(g) a) Copy and balance the equation. b) A series of fermentation experiments was carried out at different temperatures and the volume of carbon dioxide was measured. Experiment Temperature ( o C) Volume of CO2 (cm 3 ) i) Plot a line graph of these results, showing the temperature of the reaction against the volume of CO2 collected. ii) When the experiment was carried out at 70 o C, no carbon dioxide was produced. Suggest a reason for this. 13

14 Exercise 2 - Alkanols 1. a) What is the name of the functional group found in alkanols? b) Draw the structural formula for this functional group. 2. Which of the following compounds is an isomer of the following compound? 3. Name each of the alkanols for question above. 4. Draw the full structural formula for the following alkanols. a) Butan-1-ol b) Pentan-2-ol c) 2-methyl hexan-3-ol d) 3-ethyl heptan-2-ol e) Hexan-2,3-diol 14

15 Exercise 3 Alkanoic Acids 1. Draw and name the functional group found in alkanoic acids. 2. Draw the full structural formula for the following alkanoic acids. a) Ethanoic acid b) Butanoic acid c) 2-methylpropanoic acid d) 4, 4-dimethylhexanoic acid 3. a) Draw and name the full structural formula for the alkanoic acid with 5 carbons in a straight chain. b) Draw and name 2 isomers for the answer to a). 4. Using your knowledge of chemistry, discuss the uses of alkanols and alkanoic acids in society. Exercise 4 - Esters 1. Draw the structure of an ester link. 2. Draw the full structural formula for the following esters, a) Ethyl propanoate b) Methyl butanoate c) Butyl pentanoate d) Hexyl methanoate 3. Name and draw the esters produced from the following alkanols and alkanoic acids, a) Methanol & pentanoic acid b) Butanol & ethanoic acid c) Butanoic acid & propanol d) Hexanoic acid & ethanol 4. Using your knowledge of chemistry, discuss the uses of esters in society including the production of esters. 15

16 Exercise 1 Fuels Revision 2. A substance X was heated as shown. a) Which gas is produced when X is heated? b) From this experiment, what can be earned about X? 3. Petrol is an important fuel. The combustion of petrol is an example of an exothermic reaction. Explain what is meant by each of the terms underlined. 4. Many important fuels are obtained from crude oil. a) Describe how crude oil is formed. b) Explain why crude oil can be described as i) A fossil fuel ii) A finite resource c) Give TWO examples of pollution problems associated with oil. d) Name TWO other fossil fuels and describe how each is formed. 5. You are given three unlabelled cylinders of gas, using you knowledge of chemistry, describe how you would identify each cylinder from the following gases: Oxygen, nitrogen & carbon dioxide 6. Crude oil is a mixture of chemical compounds. Before the compounds can be used, the crude oil must be separated into fractions. a) Name the kind of chemical compounds found in crude oil. b) Explain what is meant by a fraction. c) Describe how crude oil is separated into fractions. d) Give a use for each of the following products obtained from oil, i) Petrol ii) Dieel iii) Gas iv) Kerosene v) bitumen 7. Explain what is meant by a) a flammable substance b) a viscous substance 16

17 8. The diagram shows the names and boiling ranges of some of the fractions which are obtained from crude oil. (c) (d) Name the process which is used to separate the crude oil into fractions. Look at the arrows for flammability and viscosity and state clearly whether they are increasing or decreasing. In which fraction is propane found? You may wish to use page 6 of the data book to help you. The table shows information about the colour of each fraction. (e) What is the colour of the fraction which is collected at 250 C? Bitumen (tar) is used for road surfacing. From which fraction is bitumen obtained? Exercise 2 For each of the following: a) Write a word equation b) Write a balanced chemical equation 1. The combustion of carbon to form carbon monoxide. 2. The combustion of carbon monoxide to form carbon dioxide. 3. The formation of water from the combustion of hydrogen. 4. The burning of ethanol (C 2H 5OH) to from water and carbon dioxide. 5. The production of water and carbon dioxide from the burning of ethane (C 2H 6). 17

18 Exercise 3 1. Complete the following table form energy values for different fuels: Fuel Mass of fuel burned (g) Energy released (kj) Energy released per gram (kj) Butane Diesel Ethanol Natural Gas Petrol Which fuel (from question 1) contains the most energy rich? 3. Make a bar graph to show the energy released per gram from each fuel. 4. The molecules of natural gas contain 1 carbon atom, the molecules of butane contain 4 carbon atoms and the molecules of petrol contain 8 carbon atoms. Use your results/graph to estimate the energy released by 1 gram of hexane (6 carbon atoms per molecule). Exercise 4 For questions 1-4, use the equation E=cmΔT, calculate the energy necessary to raise the temperature of: 1. 3 litres of water by 20 O C cm 3 of water by 30 O C. ( litres of water from 10 O C to 40 O C cm 3 of water from 5 O C to 61 O C 5. The following apparatus was used to find the energy in butanol: Use the following information to calculate the energy released per gram of butanol: Mass of burner at start Mass of burner at finish Temperature of water at start Temperature of water at end g g 20.2 O C 30.1 O C 18