Calculate the work done by a system in which a reaction results in the formation of 1.0 moles of CO2 (g) at 25 C and 100 kPa. Hint: the increase in volume will be 25 dm^3 if gas is treated as perfect.
The mechanical work done *by* a system on the environment at a constant pressure, due to a change in volume of the system is given by:
work = P * deltaV
where P is the pressure and
deltaV = final volume – initial volume
Taking the volume change given in the question, and noting that 100kPa = 10^5 Pa = 10^5 N/m^2, and that 25dm^3 = 2.5*10^-2 m^3, we have:
work = 10^5 N/m^2 * 2.5*10^-2 m^3 = 2500 N*m = 2.5kJ
The mechanical work done *by* a system on the environment at a constant pressure, due to a change in volume of the system is given by:
work = P * deltaV
where P is the pressure and
deltaV = final volume – initial volume
Taking the volume change given in the question, and noting that 100kPa = 10^5 Pa = 10^5 N/m^2, and that 25dm^3 = 2.5*10^-2 m^3, we have:
work = 10^5 N/m^2 * 2.5*10^-2 m^3 = 2500 N*m = 2.5kJ
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