Question

Given the standard heats of reaction

M(s) + 2 X2(g) → MX4(g) −113.7 kJ/mol
X2(g) → 2 X(g) +317.3 kJ/mol
M(g) → M(s) −23.1 kJ/mol

calculate the average bond energy for a single M-X bond.
Answer in units of kJ/mol.

i have an idea of how but im not fully sure

Answer 1

Add eqn 1 to 2x the reverse of eqn 2 and add to eqn 3 to get this, I think, but check it to make since I'm doing this in my head.
M(s) + 2 X2(g) → MX4(g) −113.7 kJ/mol
4X(g) → 2X2(g) -634.6 kJ/mol
M(g) → M(s) −23.1 kJ/mol
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M(g) + 4X(g) ==> MX4(g) ==> -114.7 + (-634.6) + (-23.1) = ? which is for 4 MX bonds so divide that number by 4 to get one bond. Check me out on all of this.