Question

What amount of heat must be supplied to 35 g of oxygen at room temperature to raise its temperature by 80 C at constant volume (molecular mass of oxygen is 32 and R = 8.3 J ${mol}^{-1}{K}^{-1})$

• A. 1.52 kJ
• B. 3.23 kJ
• C. 1.81 kJ
• D. 1.62 kJ

Answer 1

Answer: (C)

1.81 kJ

$C_p-C_v=R\frac{C_p}{C_v}-1=\frac{R}{C_v}\frac{7}{5}-1=\frac{R}{C_v}\frac{2}{5}=\frac{8.3}{C_v}{C}_v=\frac{5\times 8.3}{2}=20.75E=n{C}_{v}T=\frac{35}{32}\times 20.75\times 80=1815.625=1.8KJ$