InterviewSolution
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InterviewSolution
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Calculate the amount of work done in each of the following cases : (i) One mole of an ideal gas contained in a bulb of 10 litre capacity at 1 atm is allowed to enter into an evacuated bulb of 100 litre capacity. (ii) One mole of a gas is allowed of 1 atm (1 litre atm = 101.3 J) |
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Answer» (i) `W=-P_(ext)xx Delta V` As expansion takes place into the evacuated bulb, i.e., against vacuum, `P_(ext)=0`. Hence W = 0. (ii) `Delta V=V_(2)-V_(1)=5-1=4` litres, P = 1 atm `therefore W = -P Delta V = -1xx4` litre atm `=-4xx101.3J=-405.2 J` Alternatively, using the SI units directly P = 1 atm = 101325 Pa, `Delta V=4L=4xx10^(-3)m^(3)` `therefore W =-P xx Delta V=-101325xx4xx10^(-3)J=-405.3 J` The negative sign implies that the work is done by the system. |
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