20 grams of monatomic helium (molar mass of 4.0 g/mol) have a temperature of 20
ID: 1530831 • Letter: 2
Question
20 grams of monatomic helium (molar mass of 4.0 g/mol) have a temperature of 20 °C and a pressure of 1.20 atm.
The volume is then doubled while the pressure and number of moles remain the same.
e) Name the process used to do so. f) Determine the new temperature. g) Determine the heat input (or output, please specify) for the gas during this process. h) Determine the work input (or output, please specify) for the gas during this process. i) Determine the change in thermal energy for the gas during this process.
Explanation / Answer
e )
the process used to do so is " ISOBARIC "
f )
the new temperature is
T2 = V2 / V1
= 4 T1
= 4 X 293
T2 = 1172 K or 899o C
g )
Q = n Cp ( T2 - T1 )
= 5 X 2.5 X 8.314 X ( 899 - 20 )
Q = 91350.075 J
h )
W = n R ( T2 - T1 )
W = 5 X 8.314 X ( 899 - 20 )
W = 36540.03 J
i )
the internal change is = n Cv ( T2 - T1 )
= 5 X 1.5 X 8.314 X ( 899 - 20 )
= 54810.045 J
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.