The reason is because of the direction the plateaus is, so this affects it in the degree of the end result
<u>Answer:</u> The enthalpy of formation of HCN(g) is 135.1 kJ/mol
<u>Explanation:</u>
Enthalpy change is defined as the difference in enthalpies of all the product and the reactants each multiplied with their respective number of moles.
The equation used to calculate enthalpy change is of a reaction is:
![\Delta H^o_{rxn}=\sum [n\times \Delta H_f_{(product)}]-\sum [n\times \Delta H_f_{(reactant)}]](https://tex.z-dn.net/?f=%5CDelta%20H%5Eo_%7Brxn%7D%3D%5Csum%20%5Bn%5Ctimes%20%5CDelta%20H_f_%7B%28product%29%7D%5D-%5Csum%20%5Bn%5Ctimes%20%5CDelta%20H_f_%7B%28reactant%29%7D%5D)
For the given chemical reaction:

The equation for the enthalpy change of the above reaction is:
![\Delta H_{rxn}=[(2\times \Delta H_f_{(HCN(g))})+(6\times \Delta H_f_{(H_2O(g))})]-[(2\times \Delta H_f_{(NH_3(g))})+(3\times \Delta H_f_{(O_2(g))})+(2\times \Delta H_f_{(CH_4(g))})]](https://tex.z-dn.net/?f=%5CDelta%20H_%7Brxn%7D%3D%5B%282%5Ctimes%20%5CDelta%20H_f_%7B%28HCN%28g%29%29%7D%29%2B%286%5Ctimes%20%5CDelta%20H_f_%7B%28H_2O%28g%29%29%7D%29%5D-%5B%282%5Ctimes%20%5CDelta%20H_f_%7B%28NH_3%28g%29%29%7D%29%2B%283%5Ctimes%20%5CDelta%20H_f_%7B%28O_2%28g%29%29%7D%29%2B%282%5Ctimes%20%5CDelta%20H_f_%7B%28CH_4%28g%29%29%7D%29%5D)
We are given:

Putting values in above equation, we get:
![-870.8=[(2\times \Delta H_f_{(HCN(g))})+(6\times (-241.8))]-[(2\times (-80.3))+(3\times (0))+(2\times (-74.6))]\\\\\Delta H_f_{(HCN(g))}=135.1kJ/mol](https://tex.z-dn.net/?f=-870.8%3D%5B%282%5Ctimes%20%5CDelta%20H_f_%7B%28HCN%28g%29%29%7D%29%2B%286%5Ctimes%20%28-241.8%29%29%5D-%5B%282%5Ctimes%20%28-80.3%29%29%2B%283%5Ctimes%20%280%29%29%2B%282%5Ctimes%20%28-74.6%29%29%5D%5C%5C%5C%5C%5CDelta%20H_f_%7B%28HCN%28g%29%29%7D%3D135.1kJ%2Fmol)
Hence, the enthalpy of formation of HCN(g) is 135.1 kJ/mol
I think the answer is 233.748 calories
Answer:
Va = (MbVb)/Ma
Explanation:
Divide both sides by Ma and voila!