In a barometer tube of 1m long and 2cm^(2) cross -section, mercury stands at a height of 75 cm 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/cc, g = 10 ms^(-2) )

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

1.	In a barometer tube of 1m long and 2cm^(2) cross -section, mercury stands at a height of 75 cm 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/cc, g = 10 ms^(-2) )
Answer» Solution :Volume of OXYGEN `V = 2 xx (100 - 65) xx 10^(-6) = 70 xx 10^(-6) m^(3)` Pressure of oxygen, P = `rho` gh `= (13.6 xx 10^(3)) (10) (10 xx 10^(-2)) = 13,6000 Nm^(2)` TEMPERATURE oxygen T = 300 K, `therefore ` mass of oxygen, m `= (PVM)/(RT ) = 13,600 xx 70 xx 10^(-6) xx 32 xx (10^(-3))/(8.3 xx 300) ` = 0.012 gm