Question

Atmospheric pressure is 1.00 atm, but air is only composed of 21.0% (by moles) oxygen. Thus, the partial pressure of oxygen in air is less than 1.00 atm. What is the millimolar concentration of dissolved oxygen for a lake or stream under the partial pressure of oxygen and a temperature of 12 degrees celcius ?
Express the millimolar concentration numerically to two significant figures.

Answer 1

so what you need to do i think is set up a mole problem and convert the atm into moles and then do the partial pressure formual

Answer 2

i havent been in chem for a long time but i think that is right