Concentration - ppm, ppb

 

 

Concentration:

- C1V1 = C2V2(total)

- Concentration is in Molarity (M) moles solute/liters solution

- Concentration in ppm or ppb is grams solute/total grams solution

* to convert liters solution to grams solution, you need

the density of the liquid

* there are 10-6 grams in 1 ppm

there are 10-9 grams in 1 ppb

* if the concentrations are low, 1 ppm corresponds to 1

mg of solute per liter of solution

Stoichiometry and Concentration in ppm/ppb

Problem Set

1. What is the concentration of barium in ppm if 2.000 g of BaCl2 are dissloved in 6.00 L of water?

In our labs we formed AlCl3 to precipitate out the copper metal. The reaction was

3CuCl2 + 2Al -----------> 2Cu0 + 2AlCl3

2. If we added a solution of 25 ppm Al to a bucket of CuCl2, how many milligrams of copper would be formed?

 

 

 

 

3. Remember we formed CuCl2 by adding 6 M HCl to CuO. What’s the concentration of Cu2+ in ppm if 0.013 g of CuO is added to 0.5 L of 6 M HCl? (the density of 6 M HCl is 1.19 g/mL)

 

 

 

 

 

 

4. In the beginning of the copper experiment, we added NaOH to form Cu(OH)2 from a solution of Cu(NO3)2 . The Cu(NO3)2 was formed by dissolving the Cu0 in HNO3. If .0013 g of copper were dissolved in 100 mL of 12 M HNO3, how much 6 M NaOH is needed to neutralize the excess HNO3 before Cu(OH)2 could be formed?

 

 

 

 

 

 

 

 

5. What is the concentration in ppm of the Na+ ions in the solution? (assume the density of 12 M HNO3 is 1.30 g/mL and 1.05 g/mL for 6 M NaOH)