A quantity of an ideal gas is collected in a graduated tube over the mercury. The volume of gas at 20.C is 50 ml and the level of the mercury is 100mm above the outside of the mercury level. The atmospheric pressure is 750mm. Volume of gas at STP is? (Take R = 0.083 litre atm/mole )
P1 = 650 torrV1 = 50 mlT1 = 20 C + 273 = 293 KP2 = 760 TorrV2 = ?T2 = 273 Kideal gas law:P1 V1 / T1 = P2 V2 / T2rearanges to:V2 = ( P1 V1 T2 ) / ( P2 T1 )V2 = (650) (50) (273) / (760) (293)V2 = 39.84 mlrounding off, much like your "50 ml" was rounded offwould give youV2 = 40 ml