hydrogen gas has a Henry's law constant of 1.07e-6 M/mm Hg at 25 Celsius when dissolving in water. if the total pressure of gas (H2 gas plus water vapor) over water is 1.0atm, what is the concentration of H2 in the water in grams per milliliter?
1.06E-6 M/mm x 760mm = ? mols/L.
? mols/L x molar mass = g/L and convert to g/mL.
To find the concentration of H2 in the water in grams per milliliter, we need to convert the given information into appropriate units and apply Henry's law.
First, let's convert the total pressure from atm to mm Hg since the Henry's law constant is given in terms of M/mm Hg.
1 atm = 760 mm Hg
So, the total pressure of the gas (H2 gas plus water vapor) in terms of mm Hg is:
1 atm * 760 mm Hg/atm = 760 mm Hg
Now, we can apply Henry's law to find the concentration of H2 in the water.
Henry's law states that the concentration of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid. Mathematically, it can be written as:
C = k * P
where C is the concentration of the gas in the liquid, k is the Henry's law constant, and P is the partial pressure of the gas above the liquid.
Given that the Henry's law constant for hydrogen gas is 1.07e-6 M/mm Hg, and the total pressure is 760 mm Hg, we can substitute these values into the equation:
C = (1.07e-6 M/mm Hg) * (760 mm Hg)
C ≈ 0.0008152 M
Now, we have the concentration of H2 in moles per liter.
To convert this concentration to grams per milliliter, we need to use the molar mass of hydrogen, which is approximately 2 g/mol.
To convert from moles to grams, we multiply the concentration (in moles per liter) by the molar mass (in grams per mole). Since we are looking for the concentration in grams per milliliter, we divide the resulting grams by 1000 to convert from grams to milligrams and by 1000 again to convert from milligrams to grams.
C (grams per milliliter) = (0.0008152 M * 2 g/mol / 1000 mg/g) / 1000 g/mL
C ≈ 1.63e-6 g/mL
Therefore, the concentration of H2 in the water is approximately 1.63e-6 grams per milliliter.