1. Aim # 18: What are some other methods of expressing the concentration of a solution?
H.W. # 18
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2. I Solution concentration- the quantity of solute dissolved in a specific quantity of solvent or solution.
II Methods of calculating solution concentration
A. percent by mass (also called mass percent)
% = mass of solute x mass of solution
problem: What is the concentration, in percent by mass, of a solution of 30 g of sucrose in 300 g of water?
answer: g sucrose x = 9% (30g sucrose + 300g water)

3. B. parts per million (Ref. Table T)
parts per million = grams solute x grams solution
problem: If 100g of river water contains
5 x 10-4 g of Hg, what is the concentration of the mercury expressed in ppm?
ppm = g solute x g solution
= 5 x 10-4 g Hg x = 5 ppm g solution

4. answer: 6.0 x 10-3 g Pb x 106 = 3 x 101 2 x 102 g solution = 30 ppm
problem: Express the concentration in parts per million (ppm) of a solution that contains x 10-3 g Pb dissolved in every 200 g of solution.
answer: x 10-3 g Pb x = 3 x x 102 g solution = 30 ppm
C. Molarity (M) – the number of moles of solute dissolved in 1L of solution.
Molarity = moles of solute liters of solution e.g. A 1.0 molar solution (1.0 M) has mole of solute in every liter of solution.

5. problem: What is the molarity of a solution that contains 6
problem: What is the molarity of a solution that contains 6.0 moles of AgNO3 dissolved in 3.0 L of solution?
answer: M = mol = 2.0 mol/L L
problem: How many moles of NaCl are there
in 200. mL of a solution whose concentration
is M?
How many grams of NaCl are there?
mol x .200 L = mol NaCl L
mol NaCl x 58.5 g NaCl = 3.51 g NaCl mol NaCl

6. Problem: If 54. 75 g HCl is dissolved in enough water to prepare a
Problem: If g HCl is dissolved in enough water to prepare a .500 M solution, what is the volume of the solution?
54.75 g HCl x 1 mol HCl = mol HCl g HCl
1.500 mol HCl = mol HCl V L L
V = mol HCl = L mol HCl L

7. How many grams of potassium nitrate are needed to prepare 1.5 L of a 0.250 M solution?