Consider the following two reactions carried out at : (1) (2) What is the enthalpy change,

CHEMISTRY · Single correct · AP · Chemistry · Thermochemistry · Thermochemistry

Problem

Consider the following two reactions carried out at

1\,\text{atm}

: (1)

C(\text{s, graphite}) + \frac{1}{2}\,O_{2}(\text{g}) \to CO(\text{g}) \quad \Delta H_{1} = -110.5\,\text{kJ}

(2)

CO(\text{g}) + \frac{1}{2}\,O_{2}(\text{g}) \to CO_{2}(\text{g}) \quad \Delta H_{2} = -283.0\,\text{kJ}

What is the enthalpy change,

\Delta H

, in kJ, for the overall reaction

C(\text{s, graphite}) + O_{2}(\text{g}) \to CO_{2}(\text{g})

? (a)

-172.5\,\text{kJ}

(b)

-283.0\,\text{kJ}

(c)

-393.5\,\text{kJ}

(d)

+393.5\,\text{kJ}