Q.
Henry’s law constant for CO2 in water is 1.67×108Pa at 298K. What is the quantity of CO2 in 500mL of soda water when packed under 2.5 atm CO2 pressure at 298K?
Given, KH=1.67×108Pa PCO2=2.5 atm =2.5×101325Pa
Applying Henry’s law, PCO2=KH×xCO2 ∴xCO2=KHPCO2 =1.67×108Pa2.5×101325Pa=1.517×10−3
i, e. xCO2=nH2O+nCO2nCO2 =nH2OnCO2=1.517×10−3
[nCO2 is negligible]
For 500mL of soda water,
volume of water =500mL; mass of water =500g,
moles of water 18500=27.78
i.e., nCO2=27.78 ∴27.78nCO2=1.517×10−3
or nCO2=42.14×10−3 mole
Mass of CO2=42.14×10−3×44g=1.854g