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Parts Per Million (PPM)

 

This is another way of determining concentration. This is used for very small concentrations of particles in solutions.

think about this;  1ppm = 1 inch in 16 miles

As for solution ppms:

 

 

This is really just a plug and chug problem.

What is the concentration of a solution, in parts per million, if 0.02 gram of NaCl is dissolved in 1000. grams of solution?

0.02g

x 1,000,000= 20 ppm

1000.g

Then June 2007, New York State threw this curveball. Most students lost 1 of the 2 points on this one.

66. An aqueous solution has 0.0070 gram of oxygen dissolved in 1000. grams of water. In the space in your answer booklet, calculate the dissolved oxygen concentration of this solution in parts per million. Your response must include both a correct numerical setup and the calculated result. [2]

Answer-The equation above reads "grams of solution", you had to add the solute to the solvent in the denominator. Even though mathematically it didn't change a thing. It is technically wrong not to add the solute and solvents together to determine the mass of solution.

0.0070g

x 1,000,000= 7.0 ppm

1000.g + 0.0070g

YOU HAVE BEEN WARNED

Here was another one, but it was a multiple choice.

Jan 2006- 39.  If 0.025 gram of Pb(NO3)2 is dissolved in 100. grams of H2O, what is the concentration of the resulting solution, in parts per million?
(1) 2.5 10–4 ppm   (2) 2.5 ppm      (3) 250 ppm     (4) 4.0 103 ppm

0.025g

x 1,000,000= 250 ppm
100g + 0.025g

And another..and another..and yet another.

June 2005-42 What is the concentration of a solution, in parts per million, if 0.02 gram of Na3PO4 is dissolved in 1000 grams of water?
(1) 20 ppm     (2) 2 ppm   (3) 0.2 ppm  (4) 0.02 ppm

June 2008-38 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)?
(1) 0.8 ppm    (2) 8 ppm   (3) 80 ppm  (4) 800 ppm

June 2009-36 What is the total mass of solute in 1000. grams of a solution having a concentration of 5 parts per million?
(1) 0.005 g    (2) 0.05 g   (3) 0.5 g    (4) 5 g

Jan 2008-38 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)?
(1) 0.8 ppm    (3) 80 ppm
(2) 8 ppm       (4) 800 ppm

Aug 2010-15 Which unit can be used to express the concentration of a solution?
(1) L/s   (3) ppm
(2) J/g    (4) kPa

 

on to Molality  or  Colligative Properties

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