Answer to Question #286918 in General Chemistry for mia

Question

the thermochemical equation for the incomplete combustion of carbon into carbon monoxide is represented as: 2C+O2(g) = 2CO(g)

Applying hess's law, compute for the ΔH of the reaction if overall process above can occur in two steps whose thermochemical equations are given below:

1. C(s)+O2(g) = CO2(g) ΔH°= -393.5 kJ
2. 2CO(g) +O2(g) = 2CO2(g) ΔH°= -566.0 kJ

Answer 1

ROUTE 1

$2C_{(s)}+O_{2(g)}\to2CO_{(g)}\>\>\Delta\>H_2^°$

$2CO_{(g)}+O_{2(g)}\to2CO_{2(g)}\>\>\Delta\>H_3^°=-566kJ$

ROUTE 2

$2C_{(s)}+2O_{2(g)}\to2CO_{2(g)}\>\>\Delta\>H_1=(-393.5×2)kJ$

Applying Hess's Law

$\Delta\>H_1=\Delta\>H_2+\Delta\>H_3$

$-393.5×2=\Delta\>H_2+-566$

$\Delta\>H_2=-221kJ$