helium gas, 3x10-4g, is dissolved in 200g of solution. Express this concentration in parts per million.
(3x10^-4)/200 = 1/5x10^-6 = 1.5 ppm
3x10-4g, is dissolved in 200g of solution. Express this concentration in parts per million.
The easy way is to show it in percent; i.e. in parts per hundred so that is
3E-4g/200g = 1.5E4g/100g then multiply numerator and denominator by 10^4 or
1.5E-4g.......10,000
---------- X ----------- = 1.5 ppm
100g............10.000
The spacing won't look quite right but you get the idea.
Another way is to remember that ppm is mg/1000 g or
3E-4g/200 g = 0.3 mg/200 g
0.3 mg/200 x 5/5 = 1.5 mg/1000 g = 1.5 ppm
Note that oobleck made a typo. That 1/5 he meant to be 1.5.
To express the concentration in parts per million (ppm), we need to calculate the number of parts of the solute (helium gas) present per one million parts of the solution.
First, let's convert the given mass of helium gas to grams:
3x10^-4 g = 0.0003 g
Next, we calculate the concentration in ppm using the formula:
Concentration (ppm) = (Mass of solute / Mass of solution) x 10^6
Mass of solute (helium gas) = 0.0003 g
Mass of solution = 200 g
Concentration (ppm) = (0.0003 g / 200 g) x 10^6
Concentration (ppm) = 1.5 ppm
Therefore, the concentration of helium gas in the solution is 1.5 parts per million (ppm).