A vessel contains 1.6g of dioxygen at STP(273.15k,1atm pressure). The gas is now trasnferred to another vessel at constnat temperature. Whre pressure becomes half of the original pressure. Calculate
( a) Volume of the new vessel.
(b) number of molecuels of dioxygen.

Explanation

(i) 32g og oxygen at STP occupy volume = 22.4 L
1.6g of oxygen at STP occupy volume `= (22.4 L)xx((1.6g))/((32g))=1.12L`
According to available information :
`V_(1)=1.12L,P_(1)=P "atm"P,P_(2)=P//2"atm",V_(2)=?`
Apply Boyle's Law, `P_(1)V_(1)-=P_(2)V_(2)`
`V_(2)=(P_(1)xxV_(1))/(P_(2))=((P_("atm"))xx(1.12L))/((P//2"atm"))=2.24L`
(ii) 32 g og oxygen contain molecules `= 6.022 xx 10^(23)`
1.6g of oxygen contain molecules `= (6.022xx10^(23))xx((1.6g))/((32.0g))=3.011xx10^(22)`.