PPMs to mg/L

[Guest hypergloworm]

how do u convert ppms to mg/L

such as 190 ppms of chloride to - ____ mg/L

or 91 ppms of sodium to - _____ mg/L

 

 

HELP PLEASE!!!!!

[greg1917]

In solutions which the solvent is water ppm = mg/L.

 

heres the calculation anyway.

 

190 ppm chloride.

 

that means in 1000000 gm of stuff, 190 gm will be chloride.

 

ppm = (190 gm chloride) / (1000000 gm water and chloride)

 

= (190 gm chloride ) / (999810 gm water and 190 gm chloride)

 

we now know that we are dealing with 999810gm of water. since water has a density of 1kg/cubicmetre, that means we can use

 

vol = mass/density (ive converted gm into kg here)

= 999.810/ 1

=999.81 L water.

 

if we have 190 gm chloride, thats 190000 mg . we can now do the basic calculation. Note that im ignoring the volume of the chloride but if you wanted to you could calculate it using the density of chloride. Below ive said volume of solution which should include volume of both water and chloride, but as i said ive only used water. Chloride will be miniscule anyway.

 

mg/L = mass of chloride over volume of solution.

= 190000/999.81

= 190 mg/L

if you work this out youll notice you get 190.0361, if you included the volume of chloride youd get exactly 190 mg/L.

[Bsun]

Originally posted by greg1917

we now know that we are dealing with 999810gm of water. since water has a density of 1kg/cubicmetre, that means we can use

 

 

I believe water has a density of 1gram/centimeter^3. Converting these to SI units gives you:

 

1kg/ 1000g * 100^3 cm^3/m^3 = 1000kg/m^3 as the density of water. I think you may have gotten the cubicmetre and liter mixed up.

[greg1917]

I know, i meant 1kg/dm^3. the calculation is still correct, i just wrote the wrong thing while thinking the correct one.