Heat can do work.

Thermodynamics is the study of work and its transformation to other forms of energy.

Energy cannot be created nor destroyed.

calorie is equal to 4.186 J.

The internal energy of a substance is the product of molecular kinetic energy, molecular potential energy, and other kinds of molecular energy.

The first law of thermodynamics is just another version of the conservation of energy

The increase in the internal energy of a system is equal to the amount of heat added to a system plus the work done by the system.

Joule (J) is the SI unit for temperature.