The standard heat of combustion of gaseous acetylene is listed in Table B.I as —1299.6kJ/mol.

(a) In your own words, briefly explain what that means. (Your explanation should mention the reference states used to define the tabulated heats of combustion.)

(b) Use tabulated heats of formation to verify the given value of ΔH˚_c.

(c) Calculate the standard heat of the acetylene hydrogenation reaction C₂H₂ (g) + 2H₂ (g) — C₂H₆ (g) using (1) tabulated heats of formation and (ii) tabulated heats of combustion (Equation 9.4.1).

(d) Write the stoichiometnc equations for the combustion reactions of acetylene, hydrogen, and ethane, and use Hess’s law to derive the formula you used in part (c-ii).