Multiple Choice
The average atmospheric pressure in Denver is 0.830 atm. What is this pressure in kPa?
7. Gases
Pressure Units
Multiple Choice
Which value of the gas constant R should be used when pressure is given in atmospheres (atm)?
A
8.314 J·mol^{-1}·K^{-1}
B
62.4 L·mmHg·mol^{-1}·K^{-1}
C
1.987 cal·mol^{-1}·K^{-1}
D
0.0821 L·atm·mol^{-1}·K^{-1}
Verified step by step guidance1
Identify the units of pressure given in the problem, which is atmospheres (atm).
Recall that the gas constant R has different numerical values depending on the units used for pressure, volume, and energy.
Match the units of R to the units of pressure given. Since pressure is in atm, the value of R must include atm in its units.
Among the common values of R, the one with units L·atm·mol^{-1}·K^{-1} is appropriate when pressure is in atmospheres.
Therefore, the correct value of R to use when pressure is in atm is 0.0821 L·atm·mol^{-1}·K^{-1}.
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