My Phychem notes- Gases Problem Solving # 1

A mercury barometer at 25 degrees  reads 30 inches. What would be the corresponding height of the column in mm if the liquid is replaced by alcohol of density 0.78 g/cm3? show solution

PHg (density of Mercury) = 13.6 g/cm3  (1 in= 2.54 cm)

Since the second condition is in the same closed container therefore,

PHg(hHg)= Palc(halc)
where: PHg = Density of mercury
           Palc= Density of alcohol
           hHg= height of mercury
           halc= height alcohol

h=30 inches x 2.54 cm/ 1 inch= 76.2 cm

halc= PHg(hHg)/Palc= 13.6 g/cm3(76.2 cm)/0.78 g/cm3 = 1328.6 cm= 13286 mm= 1.33 x 104 mm