1. Chemical Reaction Equations….
What do they not tell us? Limitations
Limitations…..reactions do not describe or explain:
The temperature or pressure conditions in which the reaction occurred
The progress and process of the reaction
Anything about measurable quantities of reactants in any form we can use directly….total mass cannot change
Equations can be read in terms of single entities or moles of entities – NEITHER of which describes any property you can see, count or measure directly!

2. Reaction ASSUMPTIONS
So far, whether you know it or not, you have assumed that reactions are:
Fast
Spontaneous
Quantitative
Stoichiometric ( simple whole number ratios)

3. Double Replacement Reactions
Double Replacement: the cation of one substance is exchanged with the cation of another substance
Precipitation Reaction: one of the products formed is insoluble in water
ex. KCl(aq) + AgNO3(aq)  KNO3(aq) + AgCls K+
Cl-
Ag+
NO3- Ag Cl

4. Double Replacement Reactions
Write the balanced equation for the following Reactions:
Sodium sulfate and Calcium chloride
ammonium iodide and Silver nitrate
Potassium phosphate and lead ( II) Nitrate
Sodium Hydroxide and Iron (III) Chloride
Potassium sulfate and Sodium Nitrate
Sodium Carbonate and Barium Nitrate

5. Proportional Relationships
2 1/4 c. flour
1 tsp. baking soda
1 tsp. salt
1 c. butter
3/4 c. sugar
3/4 c. brown sugar
1 tsp vanilla extract
2 eggs
2 c. chocolate chips
Makes 5 dozen cookies.
I have 5 eggs. How many cookies can I make? (lots of other ingredients)
Ratio of eggs to cookies
5 eggs
5 doz.
2 eggs
= 12.5 dozen cookies

6. Proportional Relationships
Stoichiometry
mass relationships between substances in a chemical reaction
based on the mole ratio
Mole Ratio
indicated by coefficients in a balanced equation
2 Mg + O2  2 MgO

7. Information Given by the Chemical Equation
The ratio given is relative:
2 CO + O2  2 CO2
200 CO molecules react with 100 O2 molecules to produce 200 CO2 molecules
2 billion CO molecules react with 1 billion O2 molecules to produce 2 billion CO2 molecules
2 moles CO molecules react with 1 mole O2 molecules to produce 2 moles CO2 molecules
12 moles CO molecules react with 6 moles O2 molecules to produce 12 moles CO2 molecules 3

8. Solving Stoichiometry Problems

9. Ms. Wood’s Steps for Stoich
1. Write and balance equation.
2. Identify required and given and sigdigs.
3. Find the moles of given.
4. Use the mole ratio in balanced equation to find the moles of required.
Nr=Ng x R/G
5. Find what they are asking for…
6.Put answer in sig digs, with units and identify what it is then circle final answer.

10. Example #1
Determine the Number of Moles of Carbon Monoxide required to react with 3.2 moles of Oxygen Gas
CO + O2  CO2

11. Example 2
Determine the Number of grams of Iodine that will react with 35.0g of Aluminum?
Worksheet: Mass to Mass Calculations