1. Solutions, Acids and Bases
Modern Chemistry

2. Solution Solution – a homogeneous mixture of a solute and a solvent.
soluble - capable of being dissolved
Solute – the chemical that is dissolved
Solvent – the substance it is dissolved in
Ex.) Salt in water
Different types depend on state of solute/solvents:
Solid-liquid
Liquid-liquid
Gas-liquid
Liquid-gas
Solid-solid
Gas-gas

3. Mixture types Solutions Colloids Homogenous Smallest particle size
Does not separate on standing
Does not separate by filtration
Does not scatter light
Colloids
Heterogeneous
Medium particle size
Do not separate on standing
Cannot be separated by filtration
Scatters light

4. Mixtures cont. Suspensions Heterogeneous Largest particle size
Particles settle out
Can be separated by filtration
May scatter light, but are not transparent

5. A substance that dissolves in water to give a solution that conducts electric current is called an electrolyte.
Any soluble ionic compound, such as sodium chloride, NaCl, is an electrolyte.

7. Do all compounds dissolve as well as others?No
Solubility - Maximum amount of solute that can dissolve in a given amount of solvent at a given temperature

8. Factors affecting solubility
1. “Like dissolves like”
Polar solvents – dissolve ionic/polar solutes
Nonpolar solvents – dissolve nonpolar solutes
2. Pressure
No impact on solid-liquid solutions
For gas-liquid solutions,  P  Solubility
3. Temperature
Solid-liquid solutions, T Solubility
Gas- liquid solutions, T Solubility

9. Speed of solution formation
Impacted by: 1. surface area 2. agitation 3. temperature

10. Heat of solution Energy change when a solution forms
Exothermic – releases energy (hot)
Endothermic – absorbs energy (cold)

11. Once a solution forms…
Saturated solution – contains the maximum amount of solute Unsaturated solution – contains less than the maximum amount of solute Supersaturated solution – contains more than the maximum amount of solute

12. Molarity (M) Moles solute Liters solution M = mol L M =
Molarity is a standard used to express the concentration of a solution
Moles solute
Liters solution M =
mol L M =

13. Example molarity problems
You have 3.50 L of solution that contains mol of sodium chloride, NaCl. What is the molarity of that solution?
You have 0.8 L of a 0.5 M HCl solution. How many moles of HCl does this solution contain?

14. Example molarity problems
You have 8.3 L of solution that contains 205 mol of KNO3. What is the molarity of that solution?
You have 5.9 mol of HCl in a 1.5 M HCl solution. How many liters do you have?

15. Dilutions
The dilution equation is used to accurately make weaker solutions from stronger solutions by adding water
M1V1 = M2V2
Initial Molarity x initial volume = final Molarity x final volume
Stock solution
Weaker solution

16. Example
If you have 5L of a 12M HCl solution and you want a 3.5M solution, how much water should you add?
If you have 2L of a 8.5M HCl solution and you accidentally added 0.65L of distilled water, what is the new molarity?

17. Green Solution - At which cup did you stop seeing color?
Vanilla Solution
At which cup did you stop seeing color? At which cup did you stop smelling vanilla?

18. Colligative Properties
Properties that depend on the concentration of solute particles
Freezing Point Depression – add solute and the freezing point goes down
Boiling Point Elevation – add solute and the boiling point goes up

19. What are acids and bases?
Special types of solutions with specific properties

20. Properties of acids and bases
Electrolytes
Sour taste
Produce hydrogen gas when react with metal
Corrosive
React with a base to make salt + water (called neutralization)
Turn litmus red
Phenolphthalein - clear
Electrolytes
Bitter taste
Slippery
Caustic
React with acid to make salt + water (called neutralization)
Turn litmus blue
Phenolphthalein - pink
ACIDS
BASES

21. Common acids
Sulfuric
Nitric
Phosphoric
Acetic
Hydrochloric

22. Common Bases
Sodium Hydroxide
Ammonia
Aluminum Hydroxide

24. Acid Naming
Binary acid – contains only two different elements. Ex.) HCl, HF, HBr
1. The name begins with hydro-.
2. The root of the name of the second element follows.
3. The name then ends with the suffix –ic.

25. Acid Naming (cont.)
Oxyacid – is an acid that is a compound of hydrogen, oxygen, and a third element, usually a nonmetal. Ex.) HNO3, H3PO4, H2SO4
Naming: Use the root of the third element and add –ic to the end

26. Self ionization of pure water
Hydronium
Hydroxide
[H3O+] = [OH-] =1.0 X 10-7 mol/L
[H3O+] > [OH-] Acid
[H3O+] < [OH-] Base
[H3O+] = [OH-] Neutral

27. How do you find [H3O+] and [OH-]?
Use the ionization constant of water
Remember…
[H3O+] = [OH-] =1.0 X 10-7 mol/L
Therefore…
[H3O+] X [OH-] =1.0 x 10-14M

28. Given: Solution of 1.0 x 10-4 M HNO3
What is the hydronium and hydroxide concentrations?

29. Given: Solution of 1.0 x 10-2 M NaOH
What is the hydronium and hydroxide concentrations?

30. Given: Solution of 1.0 x 10-3.6 M Ca(OH)2
What is the hydronium and hydroxide concentrations?

31. pH scale
Much simpler to manage
pH scale
0-6 Acid
7 Neutral
8-14 Base

32. Calculating pH
pH = -log[H+]
pOH = -log [OH-]
pH + pOH =14

33. Determine the pH pH 3.0 1.0x10-3 M HCl pH 5.0 1.0x 10-5 M HNO3 pH 4.4
1.0 x 10-4 M NaOH
3.0x 10-2 M KOH
pH 3.0
pH 5.0
pH 4.4
pH 10.0
pH 12.48

34. Indicator
A chemical that changes color to help distinguish acids and bases
Examples:
Phenolphthalein
Red cabbage
Litmus paper
Bromothymol blue

35. Neutralization Reaction
Acidic compounds react with basic compounds neutralizing each other
Ex.)
NaOH + HCl  NaCl + H2O
Baking Powder - NaHCO3 & H2C4H4O6
Antacid