question archive A machine employs the isothermal expansion of 4
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A machine employs the isothermal expansion of 4.2 moles of ideal gas from 3.72 Lto 9.68 L. At 293°C, the machine performs 4.49 kJ of work. What percent of the maximum possible work is the machine producing? (Do not include units in your answer. If you round during your calculation make sure to keep at least 3 decimal places. Report your answer to two decimal places.) Answer: 3.30 X The correct answer is: 44.45
44.455%
Note this answer as wll as those of the substeps are rounded off to 3 decimal places.
Step-by-step explanation
Given: n = 4.2 moles
T = 29.3°C
V2 = 9.68 L
V1 = 3.72 L
Wactual = 4.49 kJ
Required: % work
Concept needed
(1) Wmax = nRTln(V1?V2??)
(2) % work = Wmax?Wactual??×100
where Wmax -- maximum/theoretical work
n -- moles
R -- universal gas constant
T -- absolute temperature
V2 -- final volume
V1 -- initial volume
Wactual -- actual work
Additional Data
R = 8.314 x 10-3 kJ/mol.K
Conversion
T, K = T,°C + 273.15
Solution
Step 1: Convert the temperature to kelvin
T = 29.3 + 273.15
= 302.45 K
Step 2: Calculate the maximum work
Wmax = (4.2 moles)(8.314 x 10-3mol.KkJ?)(302.45 K)(ln 3.72L9.68L?)
= 10.100 kJ
Step 3: Calculate % work
% work = 10.100kJ4.49kJ?×100
= 44.455%