Henry's law constant (mol/L · atm) for oxygen dissolving in blood is 3.74 *10^-² mol/L · atm at body temperature, 37°C. Calculate the molar concentration of oxygen in blood for a scuba diver where the air pressure is 2.0 atm. The mole fraction of oxygen in air is 0.209.

Question

Quizplus · Accepted Answer

According to Henry's law, the mole fraction of a gas (in this case, oxygen) in a liquid (in this case, blood) is directly proportional to the partial pressure of that gas above the liquid. We can use this relationship to solve for the molar concentration of oxygen in blood for a scuba diver where the air pressure is 2.0 atm.

The partial pressure of oxygen in air is 0.209 x 2.0 = 0.418 atm
Using Henry's law constant, we can solve for the mole fraction of oxygen in blood:
0.418 atm = (3.74 x 10^-10 mol/L x atm) x x (where x is the mole fraction of oxygen in blood)
x = 1.12 x 10^-6

Finally, we can convert the mole fraction to molar concentration by multiplying by the total molar concentration of blood, assuming it is approximately 1 mol/L:
1.12 x 10^-6 mol/L x 1 mol/L = 1.12 x 10^-6 M

Therefore, the best choice is C, 1.5 x 10^-6 M.

Henry's Law Constant (Mol/L · Atm) for Oxygen Dissolving in Blood