Q1) An ideal gas, initial volume 2.9x10 -4 m 3 , is contained by a piston in an

Question

Q1) An ideal gas, initial volume 2.9x10-4 m3, is contained by a piston in an insulated cylinder such that no heat can be lost from the gas. The initial pressure and temperature of the gas is 1.04x105 Pa and 314 K.
(a) Calculate the amount of gas, in moles, in the cylinder.
(b) The gas is then compressed to a volume of 2.9x10-5 m3 by moving the piston into the cylinder. The gas temperature rises to 790 K. Calculate the pressure in the cylinder after the compression.
(c) The work done on the gas during compression is 91 J. Use the first law of thermodynamics to find the increase in the internal energy of the gas during the compression.
[Hint – no numerical calculation is needed!]

Explanation / Answer

Using ideal gas equation        PV = n RT number of moles         n = PV/ RT = (1.04x10^5)(2.9x10^-4)/(8.314)(314)            = 0.01155 moles b) using ideal gas equation            P1 V1 / T1 = P2 V2 /T2    Final pressure          P2 = P1 V1 T2 / V2 T1    = (1.04x10^5)(2.9x10^-4)(790) /(314) (2.9x10^-5)                = 2.617x10^6 Pa c) Work done is equal to change in internal energy when no heat is added to the system             U = 91 J

Related Questions

Navigate

• Browse (All)
• Browse Q
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.