In the process of coal gasification coal is converted into a combustible mixture of carbon monoxide — Physical Chemistry Chemistry Question
Coal gasification
In the process of coal gasification coal is converted into a combustible mixture of carbon monoxide and hydrogen, called coal gas
H2O(g) + C(s) → CO(g) + H2(g)
Calculate the standard enthalpy change for this reaction from the following chemical equations and standard enthalpy changes.
2 C(s) + O2(g) → 2 CO(g) ∆rH° = –221.0 kJ mol–1
2 H2(g) + O2(g) → 2 H2O(g) ∆rH° = –483.6 kJ mol–1
Model Answer
(1) 2 C(s) + O2(g) → 2 CO(g) ∆rH° = –221.0 kJ mol–1
(2) 2 H2(g) + O2(g) → 2 H2O(g) ∆rH° = –483.6 kJ mol–1
The overall reaction is ½ (E1 – E2) ∆rH° = +131.3 kJ mol–1.
The coal gas can be used as a fuel :
CO(g) + H2(g) + O2(g) → CO2(g) + H2O(g)
Given the additional information, calculate the enthalpy change for this combustion
C(s) + O2(g) → CO2(g) ∆rH° = –393.5 kJ mol–1
Model Answer
(3) CO(g) + H2(g) + O2(g) → CO2(g) + H2O(g)
(4) C(s) + O2(g) → CO2(g) ∆rH° = –393.5 kJ mol–1
E3 = E4 + ½ E2 – ½ E1 ∆rH° = –524.8 kJ mol–1.
Coal gas can also undergo the process of methanation.
3 H2(g) + CO(g) → CH4(g) + H2O(g)
Determine the standard enthalpy change for the methanation reaction using the additional data.
CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g) ∆rH° = –802.7 kJ mol–1
Model Answer
(5) 3 H2(g) + CO(g) → CH4(g) + H2O(g)
(6) CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g) ∆rH° = –802.7 kJ mol–1
E5 = 3 E2 – ½ E1 – E6 ∆rH° = –205.7 kJ mol–1