# Hess cycle question

I'm stuck on this question it would be great if u could explain step by step thanks<3

Q. Given that the following data...

CH4 (g) + 2O2 (g) —> CO2 (g) + 2H2O(l) delta H = -890kjmol-1

CO (g) + 1/2 O2 (g) —> CO2 (g) delta H = -284kjmol-1

C(s) + O2 (g) -> CO2 (g) delta H = -393kjmol-1

H2 (g) + 1/2O2 (g) —> H2O (l) delta H = -286kjmol-1

Calculate :

A) The enthalpy of formation of methane

B) The enthalpy of formation of carbon monoxide

C) The enthalpy change when methane is burned in limited oxygen to form carbon monoxide and water
Original post by ne_ne_54
I'm stuck on this question it would be great if u could explain step by step thanks<3
Q. Given that the following data...
CH4 (g) + 2O2 (g) —> CO2 (g) + 2H2O(l) delta H = -890kjmol-1
CO (g) + 1/2 O2 (g) —> CO2 (g) delta H = -284kjmol-1
C(s) + O2 (g) -> CO2 (g) delta H = -393kjmol-1
H2 (g) + 1/2O2 (g) —> H2O (l) delta H = -286kjmol-1
Calculate :
A) The enthalpy of formation of methane
B) The enthalpy of formation of carbon monoxide
C) The enthalpy change when methane is burned in limited oxygen to form carbon monoxide and water
Your first step is to write out the equation that represents the enthalpy of formation of methane.

Your next step is to construct this equation by manipulating the other given equations.
with question 1, start out by drawing the hess' cycle and manipulate that to form an equation
-(x)+-393+-286+-286=-890 so here x is the enthalpy change of formation of methane and so you need to find x, to find the value.