Question

C (s) + O2 (g) $\longrightarrow$CO2, (g); $\Delta$H = –94.3 kcal/mol

CO (g) +$\frac{1}{2}$O2(g) $\longrightarrow$CO2 (g); $\Delta$H = – 67.4 kcal/mo!

O2(g) $\longrightarrow$2O (g); $\Delta$H = 117.4 kcal/mol

CO (g) $\longrightarrow$C (g) + O(g) ;  $\Delta$H = 230.6 kcal/mol

Calculate $\Delta$H for C (s) $\longrightarrow$C (g) in kcal/mol.

C (s) $\longrightarrow$C (g) kcal/mol$\Delta$H

• A. 171
• B. 154
• C. 117
• D. 145

Answer 1

Answer: (D)

145

Answer 2

C(s) $\longrightarrow$C(g)

can be obtained as, $\Delta$H = $\Delta$H1 – $\Delta$H2 – $\frac{1}{2}\Delta$H3 + $\Delta$H4