How many BTUs are required to heat 1 gallon of water by 1 degree Fahrenheit?

To determine how many BTUs (British Thermal Units) are needed to heat a gallon of water by 1 degree Fahrenheit, it is important to understand the specific heat of water. The specific heat of water is defined as the amount of heat required to raise the temperature of a unit mass of water by a given temperature increment. In the case of water, the mass of 1 gallon is approximately 8.33 pounds.

Since it takes about 1 BTU to raise the temperature of 1 pound of water by 1 degree Fahrenheit, the formula to calculate the total BTUs needed to heat 1 gallon (8.33 pounds) of water by 1 degree Fahrenheit would be:

1 BTU/pound × 8.33 pounds = 8.33 BTUs.

Thus, 8.33 BTUs are required to heat 1 gallon of water by 1 degree Fahrenheit. This is why the choice indicating 8.33 BTUs is the correct answer; it reflects the calculation based on the physical properties of water and provides an accurate measure for heating water.