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Question
Calculate the work done in the following reaction at 50°C. State whether work is done on the system or by the system.
`"SO"_2("g") + 1/2"O"_(2("g")) rightarrow "SO"_(3("g"))`
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Solution
`"SO"_2("g") + 1/2"O"_(2("g")) rightarrow "SO"_(3("g"))`
Δn = (moles of gaseous product) - (moles of gaseous reactant)
= 1-(1+`1/2`)
=`-1/2`
w = - ΔnRT
-( `-1/2 × 8.314 × 323`)
=1342.7J
As work done is positive. Therefore work is done by surrounding on system.
(OR)
The standard enthalpy of combustion of formaldehyde Δ 0H0 = -571 kJ How much heat will be evolved in the formation of 22 g of CO2 ?
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