Enter your answer in the provided box. pentaborane−9 (b5h9) is a colorless, highly reactive liquid that will burst into flames 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 formations of b5h9(l), b2o3(s), and h2o(l) are 73.2, −1271.94, and −285.83 kj/mol, respectively.

Answer : The heat released per gram of the compound reacted with oxygen is, 71.915 kJ

Solution :

The balanced chemical reaction is,

The expression for enthalpy change is,

where,

n = number of moles

Now put all the given values in this expression, we get

Now we have to calculate the heat released per gram of the compound reacted with oxygen.

As we know that,

1 mole of has 63.12 grams of mass

So, 2 mole of has grams of mass

As, 126.24 g of release heat = 9078.57 kJ

So, 1 g of release heat =

Therefore, the heat released per gram of the compound reacted with oxygen is, 71.915 kJ