Pentaborane-9, b5h9, is a colorless, highly reactive liquid that will burst into flame when exposed to oxygen. the reaction is 2b5h9(l) + 12o2(g) ⟶ 5b2o3(s) + 9h2o(l) calculate the kilojoules of heat released per gram of the compound reacted with oxygen. the standard enthalpy of formation of b5h9 is 73.2 kj/mol.

The amount of energy released per gram of is -71.92 kJ

Explanation:

For the given chemical reaction:

The equation used to calculate enthalpy change is of a reaction is:  

The equation for the enthalpy change of the above reaction is:

Taking the standard enthalpy of formation:

Putting values in above equation, we get:

We know that:

Molar mass of pentaborane -9 = 63.12 g/mol

By Stoichiometry of the reaction:

If 2 moles of produces -9078.57 kJ of energy.

Or,

If of produces -9078.57 kJ of energy

Then, 1 gram of will produce = of energy.

Hence, the amount of energy released per gram of is -71.92 kJ