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On a winter day, a university classroom building brings in 500 m³ of excess cold air per minute. What is the rate of heat transfer (in kilowatts) required to warm this air by 10.0ºC to room temperature?

a) 41.7 kW
b) 50.0 kW
c) 58.3 kW
d) 66.7 kW

1 Answer

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Final answer:

To warm 500 m³ of air by 10.0°C, the amount of heat needed is calculated with the specific heat capacity and density of air. The required energy is 6162.5 kJ/min, which when converted to kW results in 102.708 kW. However, this does not match any of the given answer options, indicating a possible error in the provided information.

Step-by-step explanation:

To determine the rate of heat transfer required to warm 500 m³ of air by 10.0°C, we first need to use the specific heat capacity of air and the density of air. The specific heat capacity for air at constant pressure (Cp) is approximately 1.005 kJ/kg·K, and the density of air can be taken as 1.225 kg/m³ at standard conditions. The formula to calculate the energy (Q) required in kilojoules (kJ) is:

Q = mass * specific heat capacity * temperature change

Substituting in the densities and volumes we get:

Q = (density of air * volume of air) * specific heat capacity * temperature change

Q = (1.225 kg/m³ * 500 m³/min) * 1.005 kJ/kg·K * 10 K

Q = 6162.5 kJ/min

Since power (P) is energy per unit time and 1 kilowatt (kW) is equal to 1 kJ/s, we convert the energy from kJ/min to kW by dividing by 60 (the number of seconds in a minute):

P = Q / 60 = 6162.5 kJ/min / 60 = 102.708 kW

However, none of the provided options match this calculation. It is possible there was a misprint or mistake in the given question or answer choices. Therefore, the provided options may not accurately reflect the required heat transfer rate for the stated conditions.

User Oliver Zheng
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