1. Final Review Day 3

2. Classifying Chemical Rxns
Synthesis
Decomposition
Single Replacement
Double Displacement

3. Synthesis or Direct Combination
In this type of reaction, two or more substances combine to produce a single, more-complex substance.
A +B  AB
A or B could be an element or compound
Example
2CO (g) + O2 (g)2CO2 (g)

4. Decomposition or Analysis
In this type of reaction a single substance is broken down into two or more simpler substances.
AB  A + B
AB= compound; A, B are elements
Example:
2NaCl (l)  2Na(l) + Cl2(g)

5. Single Replacement Reactions
A reaction in which an element replaces a less active element in a compound, setting the replaced element free
A + BC  AC + B
Example
Zn (s) + H2SO4 (aq)  ZnSO4 (aq) + H2 (g)
Zinc and Hydrogen switch places!

6. Double Replacement Reaction
A reaction in which two ionic compounds exchange ions to form two different ionic compounds.
AB + CD  AD + CB
Example
AgNO3 (aq) + NaCl (aq) 
AgCl (s) + NaNO3 (aq)

7. LecturePLUS Timberlake
Molarity (M)
A concentration that expresses the
moles of solute in 1 L of solution
Molarity (M) = moles of solute
1 liter solution
LecturePLUS Timberlake

8. The pH scale pH is measured On a scale from 0- 14.
pH levels from 0-6 is acidic.
pH levels from 8-14 is basic.
pH of 7 is neutral.

9. Calculating Molarity of [H+] or [OH-]
[H+] [OH-]= Kw
Kw is the ion product for water
If [H+] increases, then [OH-] decreases to keep Kw constant.
At 25 C, Kw has been found by experiment to be 1.0x10-14.
This is always true!

10. The pH of a Solution 1) pH=-log [H+] 3) [H]=10-pH
2) pH + pOH = 14 4) [H] [OH]=1x10-14
Don’t forget:
pH < 7 is acidic
pH = 7 is neutral (pure water)
pH > 7 is basic

11. What is the hydrogen-ion concentration of a solution with a pH of 8
What is the hydrogen-ion concentration of a solution with a pH of 8.00 at 25 C?
pH=-log [H+]
8.00=-log [H+]
[H+]=10-pH
[H+]=10-8
[H+]=1x10-8 M