The reaction of bromine with ethane is similar to ... - Weebly

1 The reaction of bromine with ethane is similar to that of chlorine with ethane . Three steps in thebromination of ethane are shown 1 Br2 2Br Step 2 Br + CH3CH3 CH3CH2 + HBrStep 3 CH3CH2 + Br2CH3CH2Br + Br 1(a) (i) Name this type of (ii) Suggest an essential condition for this (iii) Steps 2 and 3 are of the same type. Name this type of (iv) In this mechanism, another type of step occurs in which free-radicals combine. Namethis type of step. Write an equation to illustrate this of step .. (5)(b) Further substitution in the reaction of bromine with ethane produces a mixture of liquidorganic compounds.

2 (i) Name a technique which could be used to separate the different compounds in (ii) Write an equation for the reaction between bromine and ethane which produceshexabromoethane, C2Br6, by this substitution (2)Page 1 of 35(c) The compound 1,2-dibromo-1,1,2,2-tetrafluoroethane is used in some fire the structure of this compound. (1)(d) Halothane is used as an anaesthetic and has the following structure.(i) Give the systematic name of (ii) Calculate the Mr of (iii) Calculate the percentage by mass of fluorine in (3)(Total 11 marks) The fractions obtained from petroleum contain saturated hydrocarbons that belong to thehomologous series of alkanes.

3 (a) Any homologous series can be represented by a general formula.(i) State two other characteristics of homologous 1 ..Characteristic 2 ..2 Page 2 of 35(ii) Name the process which is used to obtain the fractions from (iii) State what is meant by the term saturated, as applied to (4)(b) Decane has the molecular formula C10H22(i) State what is meant by the term molecular (ii) Give the molecular formula of the alkane which contains 14 carbon (iii) Write an equation for the incomplete combustion of decane, C10H22, to producecarbon and water (3)(c) When petrol is burned in an internal combustion engine, some nitrogen monoxide, NO,is formed.

4 This pollutant is removed from the exhaust gases by means of a reaction in acatalytic converter.(i) Write an equation for the reaction between nitrogen and oxygen to form (ii) Identify a catalyst used in a catalytic (iii) Write an equation to show how nitrogen monoxide is removed from the exhaustgases as they pass through a catalytic (3)(Total 10 marks) Page 3 of 35 (a) Dichloromethane, CH2Cl2, is one of the products formed when chloromethane, CH3Cl,reacts with chlorine.(i) Name the type of mechanism involved in this reaction and write an equation for eachof the steps named of type of mechanism ..Initiation propagation propagation (ii) Write an overall equation for the formation of dichloromethane from (5)(b) A compound contains carbon and chlorine by mass.

5 Calculate the molecularformula of this compound, given that its relative molecular mass (Mr) is (3)(c) Suggest the formulae of two bromine -containing organic compounds formed whendibromomethane, CH2Br2, reacts with 1 ..Compound 2 ..(2)(Total 10 marks) Page 4 of 35 Chlorination of ethane follows a free-radical substitution mechanism. This mechanism is similarto that which occurs when methane is chlorinated. The overall equation for the reaction of ethaneto form chloroethane is given + Cl2 C2H5Cl + HClState the conditions and outline a mechanism for this reaction . Show how butane can be formedin this reaction .(Total 5 marks) 4 (a) (i) Name the process used to separate petroleum into (ii) Give the molecular formula for an alkane with nine carbon (iii) Write an equation for the complete combustion of the alkane (iv) Write an equation for the incomplete combustion of C11H24 to produce carbonand water (4)(b) Alkenes can be produced by cracking the naphtha fraction obtained from petroleum.

6 (i) Write an equation for the thermal cracking of one molecule of C10 H22 to giveone molecule of propene and one molecule of an alkane (ii) Draw the structure of the chain isomer of but-1-ene. (2)Page 5 of 35(c) The alkanes and the alkenes are examples of homologous series of feature of an homologous series is the gradual change in physical propertiesas the relative molecular mass increases. State two other general features of anhomologous series of 1 ..Feature 2 ..(2)(Total 8 marks) The mechanism for the reaction of methane with fluorine is a free-radical substitution similarto the chlorination of methane.(a) Outline the following steps in the mechanism for the reaction of methane with fluorine toform fluoromethane, CH3 FInitiation propagation propagation termination (4)(b) Write an overall equation for the reaction of fluorine with fluoromethane to (1)(Total 5 marks) Page 6 of 35 The percentage by mass of carbon is inA hexane.

7 (Total 1 mark)7 (a) Bromomethane, CH3Br, can be formed by a reaction between bromine and mechanism for this reaction is similar to the mechanism for the chlorinationof methane.(i) Name the mechanism for this (ii) Give the name of, and state an essential condition for, the first step in themechanism for this ..Essential condition ..(iii) Write an equation for a termination step in the mechanism for this reaction whichgives ethane as a product..(iv) Bromomethane can undergo further substitution. Write an overall equation for thereaction between bromomethane and bromine in which dibromomethane is formed..(5)Page 7 of 35(b) Bromomethane reacts with the nucleophile ammonia according to the following + 2NH3 CH3NH2 + NH4Br(i) Explain what is meant by the term (ii) Name the organic product of this (iii) Outline a mechanism for this reaction .

8 (6)(Total 11 marks) (a) State what is meant by the term homogeneous as applied to a (1)9(b) (i) State what is meant by the term (ii) Identify the species which acts as an autocatalyst in the reaction betweenethanedioate ions and manganate(VII) ions in acidic (2)Page 8 of 35(c) When petrol is burned in a car engine, carbon monoxide, carbon dioxide, oxides ofnitrogen and water are produced. Catalytic converters are used as part of car exhaustsystems so that the emission of toxic gases is greatly reduced.(i) Write an equation for a reaction which occurs in a catalytic converter between two ofthe toxic gases.

9 Identify the reducing agent in this ..Reducing (ii) Identify a transition metal used in catalytic converters and state how the converter isconstructed to maximise the effect of the metal ..How effect is (5)(d) The strength of the adsorption of reactants and products onto the surface of a transitionmetal helps to determine its activity as a heterogeneous catalyst.(i) Explain why transition metals which adsorb strongly are not usually good (ii) Explain why transition metals which adsorb weakly are not usually good (2)(Total 10 marks) The burning of fossil fuels can produce atmospheric pollutants.(a) The combustion of petrol in an internal combustion engine can lead to the formation ofcarbon monoxide, CO, and nitrogen monoxide, NO.

10 (i) Write an equation for the incomplete combustion of octane, C8H18, to produce CO andwater 9 of 35(ii) State one essential condition for the formation of NO in an engine. Write an equationfor the reaction in which NO is ..Equation ..(3)(b) All new petrol-engined cars must be fitted with a catalytic converter.(i) Name one of the metals used as a catalyst in a catalytic (ii) Write an equation to show how CO and NO react with each other in a (2)(c) State why sulphur dioxide gas is sometimes found in the exhaust gases of petrol-enginedcars. Give one adverse effect of sulphur dioxide on the for SO2 in exhaust gases.