2.2 g of an ideal gas collects over water in 1500cm³ cylinder at 27°C. Pressure of moist gas is 920 torr. What would be the molecular mass of dry hydrogen gas(vapour pressure of water at 27°C=20 torr)
Answers
Answer:
Before working with gases some definitions are needed:
PRESSURE: atmospheres or mm Hg; 1 atm = 760 mm Hg
TEMPERATURE: Kelvin, K, which is o
C + 273
STP: Standard Temperature and Pressure: 273 K and 1 atm (or 760 mm Hg)
BOYLE'S LAW (temperature is constant): PV = constant
This is an inverse relationship: if one variable increases the other must
decrease.
CHARLES' LAW (pressure is constant): V = constant x T
This is a direct relationship: if one variable increases so does the other.
GAY-LUSSAC'S LAW (volume is constant): P = constant x T
This is a direct relationship: if one variable increases so does the other.
IDEAL GAS LAW: PV = nRT, where
P = pressure of the gas sample
V = volume of the gas sample
T = Kelvin temperature of the gas sample
n = moles of the gas sample
R = molar gas constant
AVOGADRO'S LAW: At the same temperature and pressure, equal volumes of all
gases have the same number of molecules. At STP one mole of any gas occupies a
volume of 22.4 L: this is the molar volume.
PVT CHANGES: These are problems which involve only changes in the variables of Pressure,
Volume, and Temperature. The IDEAL GAS LAW can be rearranged to
PV
(1) = nR