Calculate the total pressure in a 10 litre cylinder which contains `0.4g` of helium, `1.6g` of oxygen and `1.4g` of nitrogen at `27^(@)C`. Also calculate the partial pressure of helium gas in the cylinder. Assume ideal behaviour of gases. Given `R = 0.082` litre atm `K^(-1) mol^(-1)`.

Explanation

`n_(He) = (0.4)/(4) = 0.1, n_(O_(2)) = (1.6)/(32) = 0.05`
`n_(N_(2)) = 1.4 //28 = 0.05`
`P_(He) xx V = n_(He) xx R xx T`
`P_(He) xx 10 = 0.1 xx 0.0821 xx 300`
`P_(He) = 0.2463 atm`
`P xx V = (n_(He) + n_(O_(2)) + n_(N_(2))) RT`
`P xx 10 = (0.1 + 0.05 + 0.50) xx 0.0821 xx 300`
`P = 0.4926 atm`