1. Understand the Concept

* Heat of Vaporization: The heat of vaporization (ΔHvap) is the amount of energy required to change one gram of a substance from a liquid to a gas at its boiling point. For acetone, ΔHvap = 520 J/g.

2. Calculate the Heat

* Formula: Heat (Q) = mass (m) × ΔHvap

* Plug in the values:

* Q = 43.9 g × 520 J/g

* Q = 22828 J

Answer: You would need approximately 22,828 Joules of heat to vaporize 43.9 grams of acetone at its boiling point.