Question

A sealed 2L container is completely filled with carbonated water and is refrigerated at 5 oC. Then, 10% by volume of the liquid is quickly removed by a pump at the bottom of the container. If the original container has 10g of CO2 per L, estimate the concentration of CO2 in the water (grams/L) after the 10% of the liquid is removed and the pressure. Assume a Henry’s law constant of 900 bar.

Answer 1

The volume of cotainer =2L

The concentration = 10g / L

The amount of liquid taken = 10%

two conditionsa re

a) If CO2 is also taken with water

so volume left = 1.8 L

Moles of Water = 1.8 X 1000/ 18 = 100

Mass of CO2 = 18 grams

Moles of CO2 = 18/44= 0.409

Mole fraction of CO2 = 0.409 / 100.409 = 0.0041

As per henry' law

Partial pressure of CO2 = Henry's constant x mole fraction = 900 x 0.0041 = 3.69 bars

b) only water is removed

Water amount = 1.8 L

Moles =100

CO2 = 20 g / 1.8 L = 11.11 g / L

Moles = 20 /44= 0.455

Mole fraction = 0.455/ 100.455=0.0045

Pressure = 900 X 0.0045 = 4.05 bar