Question

The density of mercury is 13.5 g/mL and the density of water is 1.00 g/mL. If a mercury barometer reads 727 mmHg, what is the barometric pressure in cmH₂O?

Answer 1

Pressure = Force / Area

Force = mass of the column * g

mass of the column = Volume * density

Volume = Area * Height

=> Pressure = Volume*density/ Area = Area*Height*density*g /Area = Height*density*g


=> Height of mercury * density of mercury * g = height of water * densidty of water * g

=> height of mercury * density of mercury = height of water *  density of water =>

height of water = height of mercury * density of mercury / density of water

height of water = 727 mmHg * 13.5 g/mL / 1.00 g/mL = 9,814.5 mmH20 =

= 981. 45 cm H2O.

Answer: 981 cm H2O