<u>Answer:</u> The 
for the reaction is 51.8 kJ.
<u>Explanation:</u>
Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.
According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.
The chemical equation for the reaction of carbon and water follows:
The intermediate balanced chemical reaction are:
(1) 
( × 2)
(2) 
( × 2)
(3) 
The expression for enthalpy of the reaction follows:
![\Delta H^o_{rxn}=[2\times \Delta H_1]+[2\times \Delta H_2]+[1\times (-\Delta H_3)]](https://tex.z-dn.net/?f=%5CDelta%20H%5Eo_%7Brxn%7D%3D%5B2%5Ctimes%20%5CDelta%20H_1%5D%2B%5B2%5Ctimes%20%5CDelta%20H_2%5D%2B%5B1%5Ctimes%20%28-%5CDelta%20H_3%29%5D)
Putting values in above equation, we get:
![\Delta H^o_{rxn}=[(2\times (-393.7))+(2\times (-285.9))+(1\times -(-1411))]=51.8kJ](https://tex.z-dn.net/?f=%5CDelta%20H%5Eo_%7Brxn%7D%3D%5B%282%5Ctimes%20%28-393.7%29%29%2B%282%5Ctimes%20%28-285.9%29%29%2B%281%5Ctimes%20-%28-1411%29%29%5D%3D51.8kJ)
Hence, the for the reaction is 51.8 kJ.
It's difficult to write it down, but I'll attach you a good example of hydroboration of indene. I hope you'll find it helpful.
We are given the equation to use which is:
ΔG = ΔH - TΔS
We are also given that:
ΔG = 173.3 kJ
T = 303 degrees kelvin
ΔH = 180.7 kJ
Substitute with these givens in the above equation to get ΔS as follows:
ΔG = ΔH - TΔS
173.3 = 180.7 - 303ΔS
303ΔS = 180.7 - 173.3
303ΔS = 7.4
ΔS = 7.4 / 303 = 0.02442 kJ/K which is equivalent to 24.42 J/k
Based on the above calculations, the correct choice is:
D. 24.42 J/K
2.258625 *10²³ oxygen atoms will be produced.
<h3><u>Explanation:</u></h3>
Decomposition reaction is defined as the type of reaction where one single reactant breaks to produce more than one product only by means of heat or other external factor.
Formula of magnesium oxide = MgO.
The molecular mass of magnesium oxide = 24 +16= 40.
So in 40 grams of magnesium oxide, number of molecules is 6.023 * 10²³.
So in 15 grams of magnesium oxide,, number of molecules is 6.023 *1023 * 15/40 = 2.258625 *10²³.
From one molecule of magnesium oxide, one oxide atom will be produced.
So number of oxide atoms with 100% yeild = 2.258625 *10²³
