Answer
$$C_{p,m} = 29.9 \space J \space K^{-1} \space mol^{-1}$$ $$C_{v,m} = 21.6 \space J \space K^{-1} \space mol^{-1}$$
Work Step by Step
$$\Delta H = C_{p} \Delta T$$ $$229 \space J = C_{p} (2.55 \space K)$$ $$\frac{229 \space J}{2.55 \space K} = C_p$$ $$C_p = 89.8 \space J \space K^{-1}$$ $$C_{p,m} = \frac{C_p}{n } = \frac{89.8 \space J \space K^{-1}}{3.0 \space mol} = 29.9 \space J \space K^{-1} \space mol^{-1}$$
$$C_{p,m} - C_{v,m} = R$$ $$C_{v,m} = C_{p,m} - R$$ $$C_{v,m} = 29.9 \space J \space K^{-1} \space mol^{-1} - 8.314 \space J \space K^{-1} \space mol^{-1}$$ $$C_{v,m} = 21.6 \space J \space K^{-1} \space mol^{-1}$$
