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Gas in a container is at a pressure of 1.4 atm and a volume of 8.0 m 3 . (a) Wha

ID: 1747991 • Letter: G

Question

Gas in a container is at a pressure of 1.4 atm and a volume of 8.0 m3. (a) What is the work done on the gasif it expands at constant pressure to twice its initial volume?
1 J

(b) What is the work done on the gas if it is compressedat constant pressure to one-quarter its initial volume?
2 J (a) What is the work done on the gasif it expands at constant pressure to twice its initial volume?
1 J

(b) What is the work done on the gas if it is compressedat constant pressure to one-quarter its initial volume?
2 J

Explanation / Answer

    Initial pressure, P = 1.4 atm                               = 1.4 X 1.013 X 10 5 Pa                               = 1.4182 X 10 5 Pa     Initial Volume, V1 = 6 m^3     Work done, W = ? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ (a)     Pressure = constant     Final volume, V2 = 2 V1     Work done at constant pressure, W = PV                                                           = P ( V2 - V1 )                                                           = P ( 2 V1 - V1 )                                                           = P V1                                                           = 1.4182 X 10 5 * 6                                                           = 8.51 X 10 5 J ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ (b)      Pressure = constant     Final volume, V2 = V1 / 4     Work done at constant pressure, W = PV                                                           = P ( V2 - V1 )                                                           = P [ ( V1 / 4) - V1 ) ]                                                           = P [ ( - 3 / 4 ) V1]                                                           = ( - 3 / 4 ) P V1                                                           = - 0.75 * 1.4182 X 10 5 * 6                                                           = - 6.38 X 10 5 J