The latent heat of vaporization of ethanol is 200 calories/gram. This means that _____.

Answer 1

Pretty general and with no context; however, this may fit.
it requires 200 calories of energy to change the phase of 1 gram of ethanol at its boiling point from liquid to vapor.

Answer 2

The latent heat of vaporization of ethanol is 200 calories/gram. This means that about 200 calories of heat must be added to 1 gram of ethanol to convert it form a liquid to a gas.

Answer 3

But that is if the liquid is at the boiling point of ethanol. If the ethanol is t a temperature lower than the boiling point then more energy is required for every degree < the b.p.