answers-chapter-17 (1).doc

Answers Chapter 17Summary Questions 17.1 p2091 ethane; homologous; functional; atom; compound; chemical2a formula of methane showing all atoms and bonds b C2H6O / C2H5OH3 have same functional group/ have same general formula / have similar chemical properties/ regular trend in physical propertiesSummary Questions 17.2 p2111 lighter; fractional; petroleum; excess; water2a butane b propene3 H H H H H C C C C H H H H H and H H H H C C C H H H H - C - H HSummary Questions 17.3 p2131 lighter; fractional; petroleum; excess; water2a methane + oxygen carbon dioxide + water b carbon + oxygen carbon dioxide c hydrogen + oxygen water3 gives out more heat / energy per grams/ non-polluting or low amount of pollution / safe to transport/ easy to use/ (readily available and cheap)Summary Questions 17.4 p2151 fractions; hydrocarbons; boiling; fractionating; higher; condense2 petroleum / crude oil heated and vaporised enters fractionation tower at bottom temperature gradient in the tower smaller/ lighter molecules move further up the tower molecules condense at places where the temperature in the column falls to just below their boiling point3a fuel for power stations, ships and home heating b fuel for jet aircraft and heating c making chemicals Chapter 17 Summary Questions p2161 naphtha making chemicals bitumen surfacing roads light gas oil fuel for diesel engines kerosene jet fuel2 ethane; homologous; alkanes; functional; alcohols; alkenes3 bitumenfuel oil kerosene naphtha refinery gas4 methane natural gas coal solid fuel petroleum thick liquid mixture fraction molecules with similar boiling points hydrogen gaseous fuel 5a -OH b C=C c -C- H d - COOH 6a compounds with the same molecular formula but different structural formulae bi H H H H H H C C C C C H H H H H H H H H H H C C C C H H H H H - C - H H H H - C - H H H H C C C H H H H - C - H H ii H H H H H C C = C C H H H H H H C = C C C H H H H H H H H C = C C H H H - C - H Hiii H H H H H C C C C O - H H H H H H H H H H C C C C H H OH H H H OH H H C C C H H H H - C - H HChapter 17 Exam Questions p216-2171 B12 C13ai group of molecules / hydrocarbons with similar boiling points1 ii compound containing carbon and hydrogen only1 b Any three of:3 temperature gradient in column or hot at bottom and cooler at top/ hydrocarbons of different sizes or masses/ rise to different level in the column/ according to their boiling points/ they condense when the temperature is just below the boiling point ci jet fuel / heating1 ii any two fractions (1 mark each) 2 any two correct uses corresponding to these fractions (1 mark each)2 see fig 17.4.2 p 215 for possible answers d fractions; shorter; lower; mass; condense (1 mark each)54a exothermic1 bi any gaseous fuel e.g. hydrogen, methane/ natural gas, 1 any liquid fuel e.g. ethanol, kerosene, petrol1 ii each of three disadvantages related to use of stated fuel (1 mark each)3 e.g. hydrogen flammable: kerosene flammable; coal sulfur dioxide formed causes breathing difficulties/ acid rain ci (hydrocarbon) with general formula CnH2n+21 ii C2H61 iii structure of methane showing all atoms and bonds1 d have same functional group/ have same general formula / have similar chemical properties/ regular trend in physical properties15a A + C1 b C1 c B1 d ethanoic acid1 e CH4O/ CH3OH1 f structural formula for an alkane other than ethane showing all atoms and bonds1 gi -OH1 ii -COOH16a mixture of hydrocarbons from the Earths crust/ under the ground;1 formed from action of heat or pressure (either) on dead animals/ plants1 b D1 c A1 d gasoline1 e 1 mark for any two fraction; 3 marks for any three correct points relating to position and/or use (from columns 2 and 3). These must be related to the fractions stated.4 for the use NOT: fuel without qualification fraction where it condenses use refinery gasabove gasolineheating/ cooking naphthabetween gasoline and kerosenemaking chemicals diesel oil/ light gas oilbelow kerosene above lubricating oilfuel for lorries fuel oilbelow kerosene above lubricating oil fuel for ships etc bitumenbelow lubricating oil for road surfaces etc7a group of compounds having have same functional group/ have same general formula / have similar chemical properties/ regular trend in physical properties1 b CnH2n+1OH1 c C