Question

Two moles of oxygen is mixed with eight moles helium. The effective specific heat of the mixture at constant volume is

• A. 1.3 R
• B. 1.4 R
• C. 1.7 R
• D. 1.9 R

Answer 1

Answer: (C)

1.7 R

Answer 2

: molar specific heat of mixture at constant volume is

$\left( C _ { V } \right) _ { \text {mixture } } = \frac { n _ { 1 } C _ { V _ { 1 } } + n _ { 2 } C _ { V _ { 2 } } } { n _ { 1 } + n _ { 2 } }$ $= \frac { 2 \times \frac { 5 R } { 2 } + 8 \times \frac { 3 R } { 2 } } { 2 + 8 } = 1.7 R$