What amount of energy is necessary to convert 1 gram of solid ice into a liquid?

To convert 1 gram of solid ice into liquid water, the process involved is known as melting or fusion. The amount of energy required for this phase change is called the latent heat of fusion. For ice, the latent heat of fusion is approximately 80 calories per gram.

This means that in order to melt 1 gram of ice at 0°C to its liquid form at the same temperature, one must provide about 80 calories of energy. This energy is used to break the hydrogen bonds that hold the water molecules in a rigid structure in the solid state.

Thus, the correct choice is based on the established scientific principle regarding the energy requirement for the melting process of ice, which is 80 calories for 1 gram.