calculate the heat of formation of methane given the heat of combustion of C,H2 and CH4 as-393,-285 and -887kj per mol respectively.
Write and balance the equations for
H2 + O2 ==>
C + O2 -->
CH4 + O2 ==>
Reverse 3 and add to 1 and 2. See if you don't get
C + 2H2 ==> CH4.
To calculate the heat of formation of methane (CH4), we can use the following equation:
ΔHf(CH4) = ΔHc(CH4) - (ΔHc(C) + 2 * ΔHc(H2))
where:
ΔHf(CH4) is the heat of formation of methane
ΔHc(CH4) is the heat of combustion of methane
ΔHc(C) is the heat of combustion of carbon
ΔHc(H2) is the heat of combustion of hydrogen
Given:
ΔHc(CH4) = -887 kJ/mol
ΔHc(C) = -393 kJ/mol
ΔHc(H2) = -285 kJ/mol
Substituting the given values into the equation, we get:
ΔHf(CH4) = -887 - (-393) - (2 * (-285))
Now let's simplify the equation:
ΔHf(CH4) = -887 + 393 - (2 * 285)
ΔHf(CH4) = -887 + 393 - 570
ΔHf(CH4) = -1071 kJ/mol
Therefore, the heat of formation of methane (CH4) is -1071 kJ/mol.