Calculate the total pressure in a 10.0 L cylinder which contains 0.4 g helium, 1.6 g oxygen and 1.4 g nitrogen at `27^@`C
`{R = 0.082 L "atm" K^(-1) "mol"^(-1)}`

Options

A. 0.492 atm
B. 49.2 atm
C. 4.92 atm
D. 0.0492 atm

Answer

A

Explanation

Number of moles of `He = 0.4/4 = 0.1`
Number of moles of oxygen = `1.6/32 = 0.05`
Number of moles of nitrogen = `1.4/28 = 0.05`
Total moles in the 10.0 L cylinder at `27^@`C
`=0.1 + 0.05 + 0.05`
= 0.2 mol
`p_(T) = (nRT)/V = (0.2 xx 0.082 xx 300)/10 = 0.492` atm