Question

1. If 103.6 mL of water is shaken with oxygen gas at 1.9 atm, it will dissolve 0.0047 g O₂. Estimate the Henry's law constant for the oxygen gas in water in units of g mL^-1atm^-1.

2. Muriatic acid is the commercial name for hydrochloric acid that can be purchased from hardware stores as a solution that is 28% (w/w) HCl. What mass of this solution contains 5.2 g of HCl?

Answer 1

1)

Henry's Law States that the solubility of a gas is directly proportional to the partial pressure of the gas above the solution. NOTE the Henry's Law only is valid at very low concentrations.

S = Kh * P

So first you need to calculate what the concentration of the substance that dissolved:

The solubility is 0.0047 g / 0.1036 L = 0.0454 g/L

0.0454 g/L / 1.9 atm = 0.0239 g * L^-1* atm^-1

2)

28% (w/w) HCl means 100g of muratic acid contains 28g of HCL

so, 100/28 g of muratic acid contains 1 g of HCL

so, 100/28 * 5.2 g of muratic acid contains 5.2 g of HCL

Answer=18.57g