Chemical thermodynamics in the manufacture of methanol

Methanol (CH3OH) is used to manufacture a large number of important

chemicals, such as formaldehyde (HCHO) which is employed in the

manufacture of a variety of polymers; methyl-tertiary-butylether ((CH3)3OCH3),

which has been used as a lead-free anti-knocking agent in petrol; acetic acid

(CH3CO₂H), etc. Annual production of methanol has been increasing: from

3.3 MTe/yr in 1982¹ to 20 MTe/yr in 1991.²

Methanol is manufactured using synthesis gas (a mixture of carbon monoxide,

CO, and hydrogen, H₂) through the following chemical equilibrium.

(a)

Use the data in Table 1 to calculate the following.

(i)The enthalpy change for the reaction, under standard conditions. Comment on your answer.

(ii) The standard entropy change for the reaction. Comment on your answer.

(iii) The standard Gibbs energy change for the reaction, under standard conditions. Comment on your answer.

(iv) The equilibrium constant for the reaction equilibrium, under

standard conditions. Comment on your answer.

(v) The change in the heat capacity at constant pressure for the

chemical reactions, under standard conditions.