2. An exothermic reaction releases 86.5 kJ. How many kilocalories of

energy are released?

20.67 kcal of energy is released.

Explanation:

It is given that, an exothermic reaction releases 86.5 kJ. We need to convet kJ to calories.

Since,

1 kcal = 4.184 kJ

So,

1 kJ = 0.239 kcal

For 86.5 kJ,

86.5 kJ = (0.239 * 86.5) kcal

86.5 kJ = 20.67 kcal

So, 20.67 kcal of energy is released.