Answer: 72.4 kJ/mol
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_{C_3H_8}\times \Delta H_{C_3H_8})]](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_%7BC_3H_8%7D%5Ctimes%20%5CDelta%20H_%7BC_3H_8%7D%29%5D)
where,
n = number of moles
(as heat of formation of substances in their standard state is zero
Now put all the given values in this expression, we get
![-2220.1=[(3\times -393.5)+(4\times -241.8)]-[(5\times 0)+(1\times \Delta H_{C_3H_8})]](https://tex.z-dn.net/?f=-2220.1%3D%5B%283%5Ctimes%20-393.5%29%2B%284%5Ctimes%20-241.8%29%5D-%5B%285%5Ctimes%200%29%2B%281%5Ctimes%20%5CDelta%20H_%7BC_3H_8%7D%29%5D)

Therefore, the heat of formation of propane is 72.4 kJ/mol
An organ.....................................................................................................
Oxygen is Earth's most abundant element by volume in Earth's Orbit
Here you are! I hope it helps, and also for the ones I put a red ‘x’ it depends on how you round it.
3.6 moles
required when each quantity of reactant completely reacts.
The ratio of the mole quantities of any two compounds present in a balanced chemical reaction is known as the mole ratio. A reaction's product yield can be predicted using mole ratios, as can the amount of reactant required to produce a specific amount of result.
The balanced chemical equation is :
(l) →
(g) +
(g)
Given is = 2.6 mol 
As we see, 3 moles of
reacts with 4 moles of
.
Therefore,
n(
) = n(
) × 
n(
) = 
n(
) = 3.6 moles.
Therefores, 3.6 moles
required when each quantity of reactant completely reacts.
Learn more about moles here;
brainly.com/question/20486415
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