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  • Given the reaction: <img alt="\mathrm{3 A(g)+2 B(g) \rightarrow C(g)+2 D(g)}" src="https://entrancecorner.oncodecogs.com/gif.latex?%5Cmathrm%7B3%20A%28g%29&plus;2%20B%28g%29%20%5Crigh

Given the reaction:

\mathrm{3 A(g)+2 B(g) \rightarrow C(g)+2 D(g)}

If the enthalpy change\mathrm{(\Delta H^{\circ})} for the reaction is -480 kJ/mol, calculate the heat released when 5 moles of A and 4 moles of B react.

Option: 1

 -2400 kJ
 


Option: 2

 -1200 kJ


Option: 3

-1300 kJ
 


Option: 4

 -900 kJ


Answers (1)

best_answer

The heat (q) released in a reaction can be calculated using the equation:

\mathrm{q=n \times \Delta H^{\circ}}

where n is the number of moles of the limiting reactant and \mathrm{\Delta H^{\circ}} is the enthalpy

change for the reaction.

Since the reaction ratio is 3A:2B, we need to determine the limiting reactant.
The number of moles of C and D formed will depend on the limiting reactant.
Calculating the moles of C and D formed:

\mathrm{Moles\; of\; \mathrm{C}=\frac{1}{3} \times Moles\; of\; \mathrm{A}=\frac{1}{3} \times 5 moles}

\mathrm{Moles \; of\; \mathrm{D}=\frac{2}{3} \times Moles\; of \; \mathrm{A}=\frac{2}{3} \times 5 moles}

The number of moles of C is less than the number of moles of D, indicating that A is the limiting reactant.
Substituting values to calculate the heat released:

\mathrm{q=5 \times-480 \mathrm{~kJ} / \mathrm{mol}=-2400 \mathrm{~kJ}}

Therefore, the heat released when 5 moles of A and 4 moles of B react is
-2400 kJ.
So, option A is correct

 

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mansi

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