Final answer:
To determine the substance that gains the most heat with a given temperature change, you look at its specific heat capacity. Chromium is a valid substance with a known specific heat capacity. However, 'Specific Heat' is not a valid substance, and without other substances for comparison, a definite answer cannot be provided.
Step-by-step explanation:
The substance that gains the greatest amount of heat when its temperature changes from 20°C to 60°C is determined by its specific heat capacity (c). Specific heat capacity is an intensive property representing the quantity of heat required to raise the temperature of 1 gram of the substance by 1 degree Celsius. This means a substance with a higher specific heat will gain more heat to increase the same amount in temperature compared to one with a lower specific heat capacity.
To answer the specific question, you would need the specific heat capacities for the substances under consideration. Unfortunately, the second option provided ('Specific Heat') is not a valid substance. The first option, Chromium, does have a specific heat capacity, but without the specific heat capacities of other substances, it's impossible to definitely say whether Chromium would gain the most heat or not.
Learn more about Specific Heat Capacity