Mole Concept And Molar Masses

We know that the concentration in ppm (parts per million) is calculated as:

%5Ctext%7Bppm%7D%20%3D%20%5Cfrac%7B%5Ctext%7BMass%20of%20solute%20(g)%7D%7D%7B%5Ctext%7BVolume%20of%20solution%20(L)%7D%7D%20%5Ctimes%2010%5E6

Given: - The molar mass of CaCO

_3

(Ca = 40 u, C = 12 u, O = 16 u) = 40 + 12 + 3(16) = 100 u
- Molar concentration =

10%5E%7B-5%7D

M
Thus, the mass of 1 mole of CaCO

_3

is 100 g. The mass of CaCO

_3

in 1 L of solution will be:

%5Ctext%7BMass%20of%20CaCO%20%5C(_3%5C)%20%7D%20%3D%20100%20%5Ctimes%2010%5E%7B-5%7D%20%3D%200.001%20%5C%2C%20%5Ctext%7Bg%7D

Now, calculating ppm:

%5Ctext%7Bppm%7D%20%3D%20%5Cfrac%7B0.001%7D%7B1%7D%20%5Ctimes%2010%5E6%20%3D%201%20%5C%2C%20%5Ctext%7Bppm%7D

Thus, the concentration of CaCO

_3

in ppm is

1

Chapter Questions
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