Question

The molar specific heat of oxygen at constant pressure C${}_p=$ $7.03$ cal/mol${}^o$C and R $=$ $8.31$ J/mol${}^o$C. the amount of heat taken by $5$ mol of oxygen when heated at constant volume from $10$${}^o$C to $20$${}^o$C will be approximately

• A. $25cal$
• B. $50cal$
• C. $250cal$
• D. $500cal$

Answer 1

The correct option is C $250cal$

Molar heat capacity at constant volume,$C_v=C_p-R$

$=5cal/molK$
No. of moles$=n=5$,

change in temperature=$\Delta T=10K$
Amount of heat absorbed=$\Delta Q=n{C}_v\Delta T$

$=(5\times 5\times 10)cal$

$=250cal$