Convert the following Celsius temperatures to Fahrenheit. -62.8 degree C, the lo
ID: 1569783 • Letter: C
Question
Convert the following Celsius temperatures to Fahrenheit. -62.8 degree C, the lowest temperature ever recorded in North America (February 3, 1947, Snag, Yukon): 56.7 degree C, the highest temperature ever recorded in the United States (July 10, 1913, Death Valley, California): Compute the specific heat capacity at constant volume of nitrogen (N_2) gas. The molar mass of N_2 is 28.0 g/mol. You warm 1.55 kg of water at a constant volume from 17.5 degree C to 28.5 degree C in a kettle. For the same amount of heat, how many kilograms of 17.5 degree C air would you be able to warm to 28.5 degree C? Make the simplifying assumption that air is 100 % N_2. What volume would this air occupy at 17.5 degree C and a pressure of 1.19 atm?Explanation / Answer
exercise 17.1 :
Part a )
C = - 62.8oC
using the conversion equation
T ( F ) = T ( C ) X 1.8 + 32
T ( F ) = - 62.8 X 1.8 + 32
T ( F ) = - 81.04 oF
Part b )
C = 56.7oC
using the conversion equation
T ( F ) = T ( C ) X 1.8 + 32
T ( F ) = 56.7 X 1.8 + 32
T ( F ) = 134.06 oF
Part c )
C = 31.1oC
using the conversion equation
T ( F ) = T ( C ) X 1.8 + 32
T ( F ) = 31.1 X 1.8 + 32
T ( F ) = 31.1 oF
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Part a )
Cv = 5R / 2 = 20.786 J/mol.K
CN2 = Cv / M
= 20.785 / 0.028
CN2 = 742 J/kg.K
Part b )
Q = m C dT
Q = 1.55 X 4186 X ( 28.5 - 17.5 )
= 71371.3 J
n = mair / M
mair = 71371.3 / 742 X ( 28.5 - 17.5 )
mair = 8.744 kg
Part c )
n = mair / M
= 8.744 / 0.028
n = 312.28 moles
V = n R T / p
V = 312.28 X 8.314 X 290.65 / 1.9 X 1.013 X 105
V = 6.2599 m3
V = 6.2599 L