What is the concentration of O2(g), in parts per million, in a solution that contains 0.008 gram of O2(g) dissolved in 1000. grams of H2O(l)?
concentration of O₂ dissolved in H₂O can be written as ppm
ppm stands for parts per million - mg/kg
the amount of mg in 1 kg of solution
the mass of O₂ - 0.008 g
1000 mg equivalent to 1 g
therefore mass of O₂ in mg - 0.008 g x 1000 mg/g = 8 mg
the mass of water is 1000 g
1000 g is equivalent to 1 kg
mass of water in kg - 1000 g / 1000 g/kg = 1 kg
there's 8 mg of O₂ in 1 kg of water
therefore concentration of O₂ is - 8 mg/kg
also can be written as 8 ppm
answer is 8 ppm
Answer : The concentration of \(O2(g)\) in parts per million is, 8 ppm
Solution : Given,
Mass of oxygen gas (solute) = 0.008 g
Mass of water (solvent) = 1000 g
First we have to calculate the mass of solution.
Mass of solution = Mass of solute + Mass of solvent = 0.008 + 1000 = 1000.008 g
Now we have to calculate the concentration of \(O2(g)\) in parts per million.
ppm : It is defined as the mass of solute present in one million \((10^6)\) parts by mass of the solution.
\(ppm=\frac{\text{Mass of solute}}{\text{Mass of solution}}\times 10^6\)
Now put all the given values in this expression, we get
\(ppm=\frac{0.008g}{1000.008g}\times 10^6=7.99=8ppm\)
Therefore, the concentration of \(O2(g)\) in parts per million is, 8 ppm