1. Chapter 13.5 Expressing solution concentration

2. Solution = Solvent + Solute
Solution – a homogenous mixture of two or more substances or components, with the major component being the solvent and the other minor components being solutes
Solvent - a substance that dissolves another substance
Or, the substance present in greater amount
Solute - a substance which is dissolved by another substance
Or, the substance present in lesser amount

3. Concentrations Concentration - amount of solute per amount of solution
There are various ways to express concentration
Dilute solution – small amount of solute relative to the amount of solvent
Concentrated solution– large amount of solute relative to the amount of solvent

5. Molarity Molarity – moles of solute per volume of solution in liters
1.00 M NaCl solution – 1 mol of NaCl(solute) in 1 liter of solution

6. Molality Molality - moles of solute per mass of solvent (in kilograms)
3.05 moles of CaSO4 in 4.60kg of H2O

7. Parts by mass
Parts by mass – a ratio of the mass of solute to the mass of the solution, then multiplied by a multiplication factor
Percent by mass
Parts per million
Parts per billion

8. Parts by volume
Parts by volume – a ratio of the volume of solute to the volume of the solution, then multiplied by a multiplication factor
Percent by volume
Parts per million
Parts per billion

9. Problems
For a soft drink that contains 10.5% sucrose (C12H22O11) by mass, what is the volume that will contain 78.5g of sucrose? Density of the solution is 1.04 (g/mL).

10. Mole fraction and mole percent
Mole fraction – (χsolute) the moles of solute per total moles in the solution (moles of solute + moles of solvent)
nx = moles of x
Mole percent – (mol%) the mole fraction as a percentage

11. Problems
With 1.37 mol of Ethanol (C2H6O) dissolved in mol of H2O, what is the mole fraction of the solution? What is the mole percent?

13. Chapter end… for now.