1.1. Butane can be converted into ethene and hydrogen which can be used in hydrogenation of vegetable oil in the presence of a nickel catalyst.

i) Write a fully balanced chemical equation including state symbols for cracking of butane.

ii) Using the data in Table 1, calculate the free energy change for this reaction. 

iii) Using your answer to part (ii) explain under what conditions this reaction would be feasible.

Table 1

1.2. The free energy change for this reaction varies with temperature.

i) Use the data in Table 2 to plot a graph of free energy against temperature on the grid below.

ii) Calculate the gradient of the line on your graph and hence calculate the entropy change, ΔS in J K mol^-1 for the formation of the cracking of butane.

Table 2

Figure 1

1.3. Hydrazoic acid is a colorless, volatile explosive liquid under standard conditions. The decomposition of the acid in a gaseous state is shown in the following equation.

HN₃ (g) →  $\frac{1}{2}$H₂ (g) + $\frac{3}{2}$N₂ (g)

Figure 1 shows a graph of graph of free energy against temperature on the grid below.

Figure 1

i) Use Figure 1 to calculate the value for ΔS for this reaction.

ii) Determine a value for ΔH for this reaction.

1.4. Use the data give in Table 2 to explain why the reaction for the formation of ethene from its elements is never feasible at any temperature. You must show your working.

Table 2