1. Concentration

2. Solution Concentration
Concentration = quantity of solute
quantity of solution (not solvent)
The main way we express concentration is using %
% concentration can be in V/V, M/M, or M/V
V/V and M/M have same units on top and bottom.
M/V is sort of in the same units;
V is mostly water and water’s density is 1 g/mL or 1 kg/L
3 g H2O/100 mL solution  3 g H2O/100 g solution

3. Mass of Solution = Mass of Solute + Mass of Solvent
Mass Percent or Percent by Mass Parts Per Hundred
% = grams of solute per 100 g of solution
5.0% NaCl has 5.0 g of NaCl in every 100 g of solution
Mass of Solution = Mass of Solute + Mass of Solvent
Divide the mass of solute by the mass of solution x by 100
Percentage concentration (V/V, M/V, M/M),
% V/V = 4.1 L / 55 L = 7.5% V/V
% M/V = 16 g / 50 mL = 32% M/V
% M/M = 1.7 g / 35.0 g = 4.9% M/M

4. Mass Percent By mass, the percent of the solution that is solute
= Mass of solute______ x 100
Mass of solute + mass of solvent
1. A 135g of seawater is evaporated, 4.73 g of salt is left.
Calculate the mass % of the salt in the seawater.
2. A 40% solution of formaldehyde is used to preserve animals.
What mass of water must be added to 425 g of solid
formaldehyde to make this solution?

5. 30 mL / 280 mL = 11% V/V (in reality may be off)
More practice
What is the % M/M of copper in an alloy when 10 g of Cu is mixed with 250 g of Zn?
What is approximate % V/V if 30 mL of pure ethanol is added to 250 mL of water?
What is the % M/M if 8.0 g copper is added to enough zinc to produce 100 g of an alloy
10 g / 260 g = 3.8 % M/M
30 mL / 280 mL = 11% V/V (in reality may be off)
8.0 g / 100 g = 8% M/M