1. Properties of Solutions
Chapter 13

2. Vocabulary: A Review A homogeneous mixture. Solution
The item dissolved.
What the solute is dissolved in.
Solution
Solute
Solvent

3. gas gas gas air, natural gas liquid gas liquid carbonated water
Types of Solutions
State of solution State of solute State of solvent
example
gas gas gas air, natural gas
liquid gas liquid
carbonated water
solid gas solid
hydrogen in platinum
liquid liquid liquid
alcohol and water
liquid solid liquid sea water solid solid solid metal alloys

4. Solution Composition Relatively little amount solute Dilute
Relatively large amount solute
Dilute
Concentrated
Molarity
Mass percent or weight percent
Mole fraction
Molality

5. Molarity versus Molality
Molarity: Moles solute/Liters solution
It is expressed as [solute] = M
Liquids change density with change in temperature.
Therefore: Molarity is not constant with temperature changes

6. Molarity versus Molality
Molality: moles solute/kg solvent
The weight of the liquid is constant with changes in temperature.

7. Question:
A solution is prepared by mixing 1.00 gram of ethanol (C2H5OH) with 100 gram water to give a final volume of 101 mL. Calculate the molarity, mass percent, mole fraction and molality of ethanol in this solution.
Molar mass of ethanol is g/mol.
mol ethanol.
Volume L
Molarity M
Mass percent:
0.990 % ethanol. (1g/101g)*100
Mole fraction: mol
5.56 mol H2O mol etOH
Molality: m
mol/0.1 kg

8. Normality A concentration measure.
Defined as the number of equivalents per liter.
For acids: The [H+] per liter
1 M HCL is 1 N HCL
1 M H2SO4 is 2 N H2SO4
For redox: The [e-] per liter or electron consumption per liter.

9. The Molar Mass, Equivalent Mass, Molarity and Normality for some acids and bases
Acid/base MM Equ M M vs N
HCL M = 1 N
H2SO /2=49 1 M = 2 N
NaOH M = 1 N
Ca(OH) /2=37 1 M = 2 N

10. Heat of solution formation
Why are some things soluble and not others?
Why does “like dissolve in like”?
Why do solution behave as they do?
Demo?

12. step
what happens                 DH 1
solute particles separate into their individual components + 2
Overcoming the IMF’s of the solvent particles make "space" or “expanding” for solute 3
solute and solvent particles "interact“ to form solution -

13. Enthalpy heat of solution
The enthalpy of the heat of a solution is the sum of the enthalpy of the three steps.
ΔH solu = ΔH 1 + ΔH 2 + ΔH 3

15. Which picture best describes a solution of HCl?

16. Probability
Why is NaCl so soluble in water if it actually takes a little energy to form a solution (4 kJ/mol)?
The mixed state is more likely to occur as there are many more ways of placing the mixed state ions in water than the one unmixed state.
Think Entropy: ΔS.

17. saturated: no more solute will dissolve    
unsaturated: able to dissolve more solute    
super-saturated: contains more solute than will dissolve under ordinary conditions