In a barometer tube of 1 m long and 2cm^(2) cross-section, mercury stands at a height of 75cm of Hg. When a small amount of oxygen is introduced in the space above the mercury, the level falls by 10 cm. Find the mass of oxygen introduced. (Room tempetature = 27^(@)C, density of mercury = 13.6 gm/c c, g=10ms^(-2))

In a barometer tube of 1 m long and 2cm^(2) cross-section, mercury sta

1.	In a barometer tube of 1 m long and 2cm^(2) cross-section, mercury stands at a height of 75cm of Hg. When a small amount of oxygen is introduced in the space above the mercury, the level falls by 10 cm. Find the mass of oxygen introduced. (Room tempetature = 27^(@)C, density of mercury = 13.6 gm/c c, g=10ms^(-2))
Answer» Solution :Volume of oxygen `V=2xx(100-65)xx10^(-6)=70xx10^(-6)m^(3)` Pressure of oxygen, `P=rhogh` = `(13.6xx10^(3))(10)(10xx10^(-2))=13,600Nm^(-2)` Temperature of oxygen T = 300 K, `therefore` MASS of oxygen, `m=(PVM)/(RT)=(13,600xx70xx10^(-6)xx32xx10^(-3))/(8.3xx300)=0.012gm`