1. INTRODUCTION TO STOICHIOMETRY
April 13, 2015
ACS Chemistry Jokes

2. Website: http://ahewagama.weebly.com/
Review
Formulas
Molar Mass
Moles
Problem solving
Website:
ENTER CLASSROOM
Class Documents
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3. Objectives
Review prior knowledge on formula, molar mass, moles and balancing equation
Complete practice worksheet. Due today at the end of the hour. You need to show your calculations along with the units to receive credit.
2/19/2019
Anura Hewagama,

4. Chemical Formula and Molar Mass
Example: Write the chemical formula for aluminum sulfate and calculate the molar mass
Al (SO4)2-
Al2(SO4)3
Step2: Count the number of atoms for each element
Al = 2
S = 1* 3 = 3
O = 4* 3 = 12
Step 3: Multiply number of atoms by their atomic mass and add them together
Al = 2 * amu = 57.96
S= 3* amu =
O = 12* amu =191.88
Total = amu
1 mole = g
2/19/2019
Anura Hewagama,

5. Conversion of Moles to Mass Calculate the mass of 2
Conversion of Moles to Mass Calculate the mass of 2.5 mole of Calcium Carbonate.
Use the conversion factor to convert moles to mass in grams
2.5 mol CaCO3 x _________ = _______ g CaCO3
2.5 mol CaCO3 x 𝑔 CaCO3 1 𝑚𝑜𝑙 CaCO3
= g CaCO3
CaCO3 Molar Mass Ca = 1* = amu C = 1* = amu O = 3* = amu Total = amu 1 mol = g
2/19/2019
Anura Hewagama,

6. Stoichiometry Tuesday April 14, 2015
Definition: Stoichiometry is the calculation of quantitative (measurable) relationships of the reactants and products in chemical reactions.
Ex. 2H2 + O H2O
Objectives:
Describe the types of relationships indicated by a balanced chemical equation
State the mole ratios from a balanced equation
State the mass ratios from a balanced equation
2/19/2019
Anura Hewagama,

7. Stoichiometry Simplified
CONVERSION FACTORS
EXAMPLE 1 - Let's make sandwiches
2 slices of bread + 1 slice of cheese grilled cheese sandwich + 
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8. Stoichiometry –Chemical Reactions
Law of Conservation of Mass
Balanced Equation
Limiting Reactants
Conversion factors
Solution to every stoichiometric calculation requires a balanced equation
Mass relationships in chemical reactions confirm law of conservation of mass
A chemical reaction stops when one chemical is used up
Solution to every stoichiometric calculation requires mole ratios as conversion factors
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Anura Hewagama,

9. Relationships Derived from Balanced Chemical Equations
𝟏 𝐦𝐨𝐥 𝐂𝟑𝐇𝟖 𝟓 𝐦𝐨𝐥 𝐎𝟐
𝟓 𝐦𝐨𝐥 𝐎𝟐 𝟏 𝐦𝐨𝐥 𝐂𝟑𝐇𝟖
𝟏 𝐦𝐨𝐥 𝐂𝟑𝐇𝟖 𝟑 𝐦𝐨𝐥 𝐂𝐎𝟐
𝟏 𝐦𝐨𝐥 𝐂𝟑𝐇𝟖 𝟓 𝐦𝐨𝐥 𝐇𝟐𝐎
2/19/2019
Anura Hewagama,