This document discusses different ways to express the concentration of solutions, including molarity, molality, mass percentage, parts per million/billion, and mole fraction. Molarity is defined as moles of solute per liter of solution. Molality is defined as moles of solute per kilogram of solvent. The document also covers topics such as mixing solutions, dilution, using molarities in stoichiometric calculations, and titration.

1. Solutions
Molarity
• Two solutions can contain the same
compounds but be quite different because the
proportions of those compounds are different.
• Molarity is one way to measure the
concentration of a solution.
moles of solute
volume of solution in liters
Molarity (M) =

2. Solutions

3. Solutions

4. Solutions
Mixing a Solution

5. Solutions
Dilution

6. Solutions

7. Solutions

8. Solutions
Using Molarities in
Stoichiometric Calculations

9. Solutions

10. Solutions
Titration
The analytical
technique in
which one can
calculate the
concentration of a
solute in a
solution.

11. Solutions
Titration

12. Solutions

13. Solutions

14. Solutions
Ways of
Expressing
Concentrations
of Solutions

15. Solutions
Mass Percentage
Mass % of A = mass of A in solution
total mass of solution × 100

16. Solutions
Parts per Million and
Parts per Billion
Parts per Million (ppm)
ppm = mass of A in solution
total mass of solution × 106
Parts per Billion (ppb)
ppb = mass of A in solution
total mass of solution × 109

17. Solutions

18. Solutions
Mole Fraction (X)
moles of A
total XA = moles in solution
• In some applications, one needs the
mole fraction of solvent, not solute—
make sure you find the quantity you
need!

19. Solutions
Molarity (M)
mol of solute
M = L of solution
• You will recall this concentration
measure from Chapter 4.
• Because volume is temperature
dependent, molarity can change with
temperature.

20. Solutions
Molality (m)
mol of solute
m = kg of solvent
Because both moles and mass do not
change with temperature, molality
(unlike molarity) is not temperature
dependent.

21. Solutions

22. Solutions
Conversion of concetration
units

23. Solutions

24. Changing Molarity to Molality
Solutions
If we know the
density of the
solution, we can
calculate the
molality from the
molarity, and vice
versa.