Using henry's law, calculate the molar concentration of o2 in the surface water of a mountain lake saturated with air at 20 ∘c and an atmospheric pressure of 685 torr .

The molar concentration of oxygen gas in water is .

Explanation:

Partial pressure of the gas = 685 torr = 0.8905 bar

1 torr = 0.0013 bar

According Henry's law:

Value of Henry's constant of oxygen gas at 20 °C in water = 34860 bar

Let the number of moles of gas in 1 liter water be n.

1 Liter water = 1000 g of water

Moles of water in 1 L

Molar concentration of oxygen gas in 1 L of water:

The molar concentration of oxygen gas in water is .

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.