cal/g

calorie per gram

Specific latent heatexact by definition

The calorie per gram is the historical metric unit of latent heat, equal to exactly 4184 J/kg using the thermochemical calorie of 4.184 joules. The factor is exact by definition of that calorie. In these units water's heat of fusion is about 80 cal/g and its heat of vaporisation about 540 cal/g, two numbers that generations of chemistry students memorised.

Watch out: Several calories differ by roughly one part in a thousand. This catalog uses the thermochemical calorie of exactly 4.184 J; the International Table calorie is 4.1868 J. Older tables rarely say which they mean.

1 cal/g 4,184 J/kg