1. Stoichiometry
ICS III
Week 6

2. Baking Recipe Ingredients Makes up to 50 cookies (Co)
1 cup unsalted butter (B)
1 cup sugar (S)
1 cup brown sugar (Bs)
2 large eggs (E)
1 teaspoon pure vanilla extract (V)
3 cups flour (F)
1 teaspoon salt (Na)
2 cups chocolate chips (Cc)
Bake for degrees OF
Makes up to 50 cookies (Co)

3. Chemical Reactions Chemical reaction
When bonds are broken and rearranged to form a new substance
Reactant(s)
A substance present at the start of a reaction
You can have 1 reactant or 1,000 reactants
Product(s)
Substance produced in a chemical reaction
You can have 1 product or 1,000 products

4. Chemical Equation A representation of a chemical reaction
Yields
REACTANT REACTANT 2
PRODUCT PRODUCT 2
Chemical Equation
A representation of a chemical reaction
The formulas of the reactants (on the left) are connected by an arrow with the formulas of the product (on the right).

5. Baking Recipe Ingredients Makes up to 50 cookies (Co)
1 cup unsalted butter (B)
1 cup sugar (S)
1 cup brown sugar (Bs)
2 large eggs (E)
1 teaspoon pure vanilla extract (V)
3 cups flour (F)
1 teaspoon salt (Na)
2 cups chocolate chips (Cc)
Bake for degrees OF
Makes up to 50 cookies (Co)
Letters are symbols that indicate a specific compound. B = butter
Reactants
Product

6. Chemical Reaction for Baking Chocolate Chip Cookies
1 cup unsalted butter (B)
1 cup sugar (S)
1 cup brown sugar (Bs)
2 large eggs (E)
1 teaspoon pure vanilla extract (V)
3 cups flour (F)
1 teaspoon salt (Na)
2 cups chocolate chips (Cc)
Bake for degrees OF
Makes up to 50 cookies (Co)
When ever you don’t put a number, it automatically indicates only 1 compound
B + S + Bs + E + V + F + Na + Cc  Co
B + S + Bs + 2E + V + 3F + Na + 2Cc  50Co
Coefficient
A number that represents how many compounds are present in a reaction

7. + + + Making a Bicycle F + 2W + H + 2P --- FW2HP2
Frame wheels + handlebar + 2 pedals bicycle
F + 2W + H + 2P --- FW2HP2
Product
Reactants

8. Conservation of Mass
In a chemical reaction mass and atoms are conserved in every chemical reaction.
What ever is on the left must equal what is on the right.
__ grams + 40 g = 77 g
37 grams

9. Stoichiometry Stoichiometry Mole Ratio
Calculation of quantities in chemical reactions
Allows chemists to tally the amounts of reactants and products using ratios of moles or representative particles.
Mole Ratio
Conversion factor derived from the coefficients of balanced chemical equations interpreted in terms of moles

10. How Stoichiometry Works
If you react 20 grams of sodium hydroxide with an excess of hydrochloric acid, how much water would result?
You always want to work with moles!
Go through the steps
What is given
What are you looking for?
How do we get there?

11. How Stoichiometry Works
What is given?
20 grams NaOH
What are we looking for?
Grams water (H2O)
How do we get there??
Convert to moles
Mole ratio
Convert to grams

12. Mole Ratio Moles of wanted compound Moles of given compound
The coefficient goes in front

13. How Stoichiometry Works
What is given
Convert from moles to grams
MOLE RATIO
Convert from grams to moles
What is wanted

14. How Stoichiometry Works
In this reaction, how many grams of Fe2O3 are required to completely react with 84 grams of CO?
What is given
Convert from moles to grams
MOLE RATIO
Convert from grams to moles
What is wanted

15. aG bW
(given quantity) (wanted quantity)

16. aG bW
(given quantity) (wanted quantity)

17. aG bW
(given quantity) (wanted quantity)

18. CH4 + 2O CO2 + 2H2O
The Equation above shows the reaction of methane (CH4) burning in the presence of oxygen. If 32 grams of methane react completely with oxygen, how many grams of carbon dioxide (CO2) will be formed?
32 g
44 g
56 g
88g