A cylinder contains \(0.6 \mathrm{~m}^{3}\) of gas at a pressure of 1 bar and \(90^{\circ} \mathrm{C}\) the gas is compressed to a volume of \(0.18 \mathrm{~m}^{3}\) according to law \(P V^{\mathrm{n}}=\mathrm{C}\). The final pressure is 5 bar. Assuming R \(=0.287 \mathrm{KJ} / \mathrm{Kg} \mathrm{K}\) and \(\gamma=1.4\) Calculate: (i) The mass of gas, and (ii) The Value of Index \(n\) for compression.