A two litre flask contains a mixture of 16g of oxygen, 7g of nitrogen and 2g of hydrogen at `20^@C`. Report the total pressure and partial pressures.

Explanation

Total number of moles of mixture `= (" 16g of" O_2)/( 32 g mol^(-1) ) +( 7 g " of " N_2) /( 28 g mol^(-1)) +(2g " of" H_2)/(2 g mol^(-1))=1/2 +1/4 +1=7/4`
Using ideal gas equation,
`P=n (RT)/(V ) = 7/4 xx ( 0.0821 xx 293 )/( 2 ) = 21 atm`
Partial pressure of oxygen `= (" number of moles of "O_2)/(" total number of moles " ) xx` pressure `=1/2 xx 4/7 xx 21 = 6 atm `
Similarly, partial pressure of nitrogen` = 1/4 xx 4/7 xx 21 = 3 atm `
Partial pressure of hydrogen `1/1 xx 4/7 xx 21 = 12 atm`