7. Henry’s law constant for CO₂ in water is 1.67 x 10⁸ P_a at 298 K. Calculate the quantity of CO₂ in 500 mL of soda water when packed under 2.5 atm CO₂ pressure at 298 K.

Solution :
given that, 
pressure of CO₂=2.5atm
1 atm = 1.01325x 10⁵ pa  so that 
pressure of CO₂ = 2.5x1.01325x10⁵pa
   = 2.533125 x 10⁵ pa
K_H = 1.67 x 10⁸ pa
ACcording to henry's law  p= K_H*X
or X=P/K_H 
     = 2.533125 x 10⁵/1.67x 10⁸
     = 1.52 x 10^-3

But we have 500ML odf soda water so that 
Volume of water = 500mL
Density of water =1g/ml
mass = volume x density 
500 mL of water = 500g of water
molar mass f water (H₂O) = 18g mol^-1
number of moles =