Gas Fitter Practice Test

A British Thermal Unit (BTU) is the amount of heat required to:

1. Raise the temperature of one pound of water by one degree Fahrenheit

2. Raise the temperature of one pound of a substance by one degree Fahrenheit

3. Change one pound of a substance from a liquid to a vapor

4. Change one pound of ice to water at 32 degrees Fahrenheit

The correct answer is: Raise the temperature of one pound of water by one degree Fahrenheit

The correct answer is based on the definition of a British Thermal Unit (BTU), which is specifically defined as the amount of heat necessary to raise the temperature of one pound of water by one degree Fahrenheit. This definition highlights the BTU's focus on water, a standard reference point in thermodynamics because of its unique thermal properties. This definition is crucial for understanding various heating and cooling applications, including residential heating systems and appliance specifications, where the effectiveness of these systems is often measured in BTUs. The other options do not accurately represent the specific meaning of a BTU: - The second option relates to raising the temperature of one pound of a general substance, not specifically water, which broadens the definition and deviates from the standard usage of BTU. - The third option discusses a phase change (liquid to vapor) rather than a temperature increase, which involves a different measurement unit called the latent heat of vaporization, not a BTU. - The fourth option refers to the heat needed to melt ice, which involves a phase change as well, distinguishing it again from the straightforward concept of a BTU. Understanding that a BTU is specifically about heating water by a certain degree is fundamental in fields like gas fitting, where evaluating energy needs