Final answer:
The mass of the melted chocolate is the same as the solid chocolate, 8 grams, due to the Law of Conservation of Mass.
Step-by-step explanation:
When a piece of chocolate with a mass of 8 grams melts, the mass of the melted chocolate remains the same, at 8 grams. This is because the Law of Conservation of Mass states that mass is neither created nor destroyed in a chemical reaction or physical change. Therefore, melting, which is a physical change, does not alter the amount of matter.