In the combustion of carbon to form methane, the change in enthalpy is -652 kJ
C(g) + 4H(g) ® CH4(g) DH = −652 kJ
What will be the value of DH for the process 1/2C(g)+ 2H(g) ® 1/2CH4(g) DH = ?
-652kJ
+652kJ
-326kJ
+326 kJ
-326 kJ
To find the value of ΔH for the given process 1/2C(g) + 2H(g) → 1/2CH4(g), we can use the concept of Hess's Law.
Hess's Law states that the enthalpy change of a reaction depends only on the initial and final states of the reaction and is independent of the path taken.
In this case, we can see that the equation for the given process is exactly half of the equation for the combustion of carbon to form methane. Therefore, the ΔH value for the given process is also half of the ΔH value for the combustion of carbon.
ΔH for the process 1/2C(g) + 2H(g) → 1/2CH4(g) = 1/2 × (-652 kJ)
= -326 kJ
So, the correct answer is -326 kJ.