How much heat is needed to increase the temperature of 20 lb of water from 32°F to 212°F?

Study for the HVAC Refrigeration Fundamental Test with flashcards and multiple choice questions. Each question comes with hints and explanations. Get ready for your exam!

Multiple Choice

How much heat is needed to increase the temperature of 20 lb of water from 32°F to 212°F?

Explanation:
To determine the amount of heat needed to increase the temperature of a certain mass of water, you can use the formula: \[ Q = m \times C \times \Delta T \] where: - \( Q \) is the heat energy in BTUs, - \( m \) is the mass of the water in pounds, - \( C \) is the specific heat capacity of water (approximately 1 BTU/lb°F), - \( \Delta T \) is the change in temperature in degrees Fahrenheit. In this case, the mass of water is 20 lb, the initial temperature is 32°F, and the final temperature is 212°F. First, we need to calculate the change in temperature (\( \Delta T \)): \[ \Delta T = 212°F - 32°F = 180°F \] Now, substitute the values into the formula: \[ Q = 20 \, \text{lb} \times 1 \, \text{BTU/lb°F} \times 180°F \] Calculating that gives: \[ Q = 20 \times 180 = 3600 \, \text{BTU} \] Thus, the amount of heat required to

To determine the amount of heat needed to increase the temperature of a certain mass of water, you can use the formula:

[ Q = m \times C \times \Delta T ]

where:

  • ( Q ) is the heat energy in BTUs,

  • ( m ) is the mass of the water in pounds,

  • ( C ) is the specific heat capacity of water (approximately 1 BTU/lb°F),

  • ( \Delta T ) is the change in temperature in degrees Fahrenheit.

In this case, the mass of water is 20 lb, the initial temperature is 32°F, and the final temperature is 212°F. First, we need to calculate the change in temperature (( \Delta T )):

[ \Delta T = 212°F - 32°F = 180°F ]

Now, substitute the values into the formula:

[ Q = 20 , \text{lb} \times 1 , \text{BTU/lb°F} \times 180°F ]

Calculating that gives:

[ Q = 20 \times 180 = 3600 , \text{BTU} ]

Thus, the amount of heat required to

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