Number 3 i think is <span>d.heat moves from an object of higher temperature to an object of lower temperature</span>
I think the answer is A or C sorry for not having that good of an answer
Answer: The enthalpy change for this reaction is, -803 kJ
Explanation:
The balanced chemical reaction is,

The expression for enthalpy change is,
![\Delta H=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5Csum%20%5Bn%5Ctimes%20%5CDelta%20H_f%28product%29%5D-%5Csum%20%5Bn%5Ctimes%20%5CDelta%20H_f%28reactant%29%5D)
![\Delta H=[(n_{CO_2}\times \Delta H_{CO_2})+(n_{H_2O}\times \Delta H_{H_2O})]-[(n_{O_2}\times \Delta H_{O_2})+(n_{CH_4}\times \Delta H_{CH_4})]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5B%28n_%7BCO_2%7D%5Ctimes%20%5CDelta%20H_%7BCO_2%7D%29%2B%28n_%7BH_2O%7D%5Ctimes%20%5CDelta%20H_%7BH_2O%7D%29%5D-%5B%28n_%7BO_2%7D%5Ctimes%20%5CDelta%20H_%7BO_2%7D%29%2B%28n_%7BCH_4%7D%5Ctimes%20%5CDelta%20H_%7BCH_4%7D%29%5D)
where,
n = number of moles
Now put all the given values in this expression, we get
![\Delta H=[(1\times -394)+(2\times -242]-[(2\times 0)+(1\times -75)]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5B%281%5Ctimes%20-394%29%2B%282%5Ctimes%20-242%5D-%5B%282%5Ctimes%200%29%2B%281%5Ctimes%20-75%29%5D)

Therefore, the enthalpy change for combustion of methane is, -803 kJ