The combustion of 1 mole of co according to the reaction co(g) + ½o2(g) → co2(g) + 67.6 kcal gives off how much heat?

When the enthalpy value is given, we can calculate how much heat is use or produces in a given equation. 

67.6 kCal ---> 67.6 kCal= 1 mol of reaction
1 mol of reaction=  1 mol of CO (based on the coefficient)

so 1 mole of CO gives us 67.6 kCal of heat.

calculation:

1 mol CO

The answer is c. 320 g