In the combustion of carbon to form methane, the change in enthalpy is -652 kJ
C(g) + 4H(g) rightwards arrowCH4 (g) incrementH = −652 kJ
What will be the value of incrementH for the process 1 halfC (g)+ 2H (g) rightwards arrow 1 halfCH4 (g) incrementH = ?
-326 kJ
+652 kJ
-652 kJ
+326 kJ
-326 kJ
+652 kJ
-652 kJ
+326 kJ
The chemical equation for combustion of carbon to form methane involves 1 mol of carbon and 4 mol of hydrogen. To get the desired equation that relates the formation of 1/2 mol of methane, we need to divide the original equation by 8, giving:
1/2 C(g) + 2H(g) → 1/2 CH4(g)
Since the coefficients of the species in the balanced equation are all divided by 8, the change in enthalpy must also be divided by 8. Therefore:
ΔH = (-652 kJ)/8 = -81.5 kJ
So the answer is -326 kJ.
To find the value of ΔH for the process 1/2 C (g) + 2H (g) → 1/2 CH4 (g), we can use the stoichiometry of the balanced equation for the combustion of carbon to form methane.
From the balanced equation given, we can see that 1 mole of carbon (C) reacts with 4 moles of hydrogen (H) to form 1 mole of methane (CH4).
Therefore, to calculate the ΔH for the new process, we need to consider that we have 1/2 mole of carbon reacting with 2 moles of hydrogen to form 1/2 mole of methane.
From the given ΔH value of -652 kJ for the combustion of carbon to form methane, we can determine the new ΔH value by using the stoichiometry:
ΔH = (-652 kJ / 1 mole) * (1/2 mole CH4 / 1 mole C)
= -326 kJ
Therefore, the value of ΔH for the process 1/2 C (g) + 2H (g) → 1/2 CH4 (g) is -326 kJ.
So, the correct answer is -326 kJ.