A sample of air was collected to assess the safety level of nitrogen trichloride in the air around a swimming pool. It was found that the air contained 0.0025% by mass of nitrogen trichloride. Calculate the molar concentration of nitrogen trichloride in the sample collected.
The Attempt at a Solution
I know that mole is directly proportional to volume for gas. But it's percentage by mass. I have no idea how to do this.
The answer is 2.07x10^-4 moldm^-3 .
Can anyone explain to me or give me some clues?
I know that air is a mixture and should be done differently from finding empirical formula of a compound.