i) The enthalpy change to convert methane into gaseous atoms is shown below.
Calculate the average bond enthalpy of a C—H bond in methane. 
ii) Use the data in the table below and your answer to (a)(i) to calculate the enthalpy
b) The standard enthalpy of formation of 1,2-dibromoethane, CH2BrCH2Br, is – 37.8 kJmol-1.
Suggest the main reason for the difference between this value and your calculated value in (a)(ii).
2. . a) Define the term standard enthalpy of combustion. 
b) Write an equation for the complete combustion of ethanol, C2H5OH 
c) The following table gives some standard enthalpies of formation.
Use these data to calculate a value for the enthalpy of combustion,∆Hc , ofpropan-1-ol, C3H7OH
C3H7OH(l) + 4 O2(g) → 3CO2(g) + 4H2O(l) 
d) State how you would expect the value obtained in part (c) to differ if gaseous water, rather than liquid
water, is formed. 
e) In an experiment 0.92 g of propan-1-ol, C3H7OH, was burned and the heat given off used to raise the temperature of 250 g of water. The temperature rise was 16 °C. The specific heat capacity of water is 4.2 JK–1 g–1.
Calculate a value for the enthalpy of combustion of one mole of propan-1-ol. 
f) Suggest why the experimental value of the enthalpy of combustion obtained in part (e) is less reliable than the value obtained in part (c). 
3. a) Explain the meaning of the term enthalpy change of a reaction. 
b) Write an equation, including state symbols, for the reaction that represents the standard enthalpy of
formation, ∆Hf , of liquid carbon disulphide (CS2). 
c) Carbon disulphide is flammable and burns in air according to the following equation.
Using this equation and the data below, calculate a value for the standard enthalpy of... [continues]
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