Two litres of an ideal gas at a pressure of $$10$$ $$atm$$ expands isothermally into a vacuum until its total volume is $$10$$ litres. How much heat is absorbed and how much work is done in the expansion ?
A.
$$10\,J,10\,J$$
B.
$$8\,J,10\,J$$
C.
$$18\,J,0\,J$$
D.
$$0\,J,0\,J$$
Answer :
$$0\,J,0\,J$$
Solution :
$$q = - w = {P_{ex}}\left( {10 - 2} \right) = 0\left( 8 \right) = 0$$
For isothermal expansion in vacuum, $${P_{ex}} = 0$$
Releted MCQ Question on Physical Chemistry >> Chemical Thermodynamics
Releted Question 1
The difference between heats of reaction at constant pressure and constant volume for the reaction : $$2{C_6}{H_6}\left( l \right) + 15{O_{2\left( g \right)}} \to $$ $$12C{O_2}\left( g \right) + 6{H_2}O\left( l \right)$$ at $${25^ \circ }C$$ in $$kJ$$ is
$${\text{The}}\,\Delta H_f^0\,{\text{for}}\,C{O_2}\left( g \right),\,CO\left( g \right)\,$$ and $${H_2}O\left( g \right)$$ are $$-393.5,$$ $$-110.5$$ and $$ - 241.8\,kJ\,mo{l^{ - 1}}$$ respectively. The standard enthalpy change ( in $$kJ$$ ) for the reaction $$C{O_2}\left( g \right) + {H_2}\left( g \right) \to CO\left( g \right) + {H_2}O\left( g \right)\,{\text{is}}$$