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 change its temperature about 200 calories of heat must be added to 1 gram of ethanol to convert it from a solid to a liquid about 200 calories of heat must be added to 1 gram of ethanol to convert it from a liquid to a gas

Heat of vaporization refers to the amount of energy required to vaporize some amount of a substance depending on the units.  Since the units in this case is calories/gram, 200 calories are required to vaporize 1 gram of ethanol.  This means that it takes 200 calories to convert 1 gram of ethanol from a liquid to a gas.

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Answer) by studying proton collisions hope this : )