Final answer:
The heat energy needed to melt 65g of ice at 0°C is calculated by multiplying the mass (65g) by the specific heat of fusion for water (79.9 cal/g), giving a total of 5193.5 cal.
Step-by-step explanation:
The heat energy required to melt 65g of H2O, also known as ice, can be calculated using the heat of fusion. The question is related to the phase change of water from solid to liquid, which occurs at 0°C when heat is applied.
The heat of fusion for water is a known value, which is 79.9 cal/g according to the given reference example. To find the total heat necessary for melting, you multiply the mass of the ice by the heat of fusion:
Heat energy required = Mass of H2O x Heat of fusion
Heat energy required = 65g x 79.9 cal/g
Heat energy required = 5193.5 cal
Therefore, to melt 65g of ice at 0°C, one would require 5193.5 calories of heat energy.