CHAPTER 9 STOICHIOMETRY

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CHAPTER 9 STOICHIOMETRY

• STOICHIOMETRY IS THE BRANCH OF CHEMISTRY THAT
  DEALS WITH
• A) MASS RELATIONSHIPS OF ELEMENTS IN COMPOUNDS
• B) MASS RELATIONSHIPS BETWEEN REACTANTS AND
  PRODUCTS IN CHEMICAL REACTIONS.
• 1) COMPOSITION STOICHIOMETRY- DEALS WITH MASS
  RELATIONSHIP OF ELEMENTS IN COMPOUNDS. (Uses
  subscripts Oxidation s)
• (LAW OF DEFINITE COMPOSITION MULTIPLE
  PROPORTIONS) (Chap3)
• 2) REACTION STOICHIOMETRY- DEALS WITH MASS
  RELATIONSHIPS
• AMONG REACTANTS AND PRODUCTS IN A CHEMICAL
  REACTION
• (BALANCED EQUATIONS CONSERVATION OF MASS)

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4 TYPES OF REACTION-STOICHIOMETRY PROBLEMS

• 1) MOLE - MOLE, MOLES OF A -gt MOLES OF B
• 2H2 O2 ? 2H2O
• 2 mols 1 mol ? 2 mols
• 6 mols __mols ?____mols
• 2) MOLE - MASS, MOLES OF A -gt MOLES OF B -gt MASS
  OF B
• 2H2 O2 ? 2H2O
• 2 mols 1 mol ? 2 mols
• 6 mols 3 mols ?__6__mols
• Mass of O2 ____and mass of water____
• Mols of O2 x 32g mass of O2 96g)
• 1 MOL
• Mols of water x 18g mass of water (108g)
• 1 MOL

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• 3) MASS-MOLE,
• MASS OF A -gt MOLS OF A -gt MOLS OF B
• 2H2 O2 ? 2H2O
• 2 mols 1 mol ? 2 mols
• 28g OF Hydrogen produces _______mols of water
• 28g x 1mol x 2mol H20 mols of water
• 2g 2mols H2
• 4) MASS-MASS,
• MASS A -gt MOLES A -gt MOLES B -gt
  MASS OF B
• 28g of Hydrogen produces _______grams of water
• 28g x 1mol x 2mol H20 mols of water x 18g
• 2g 2mols H2
  1 mol water

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CONVERSION FACTORS

• MOLAR MASS AND MOLE RATIO
• MOLE RATIO - CONVERSION FACTOR THAT RELATES OF
  MOLES OF ANY 2 SUBSTANCES IN A REACTION
  COEFFICIENTS
• Molar Mass Mass of a mole,
• - Formula mass in grams

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Solving Problems

• TO SOLVE REACTION STOICHIOMETRY PROBLEMS
• 1. BALANCE EQUATION
• 2. DETERMINE WHAT IS GIVEN AND WHAT IS
  REQUIRED. (Read Problem)
• (GIVEN MOLES OR MASS - REQUIRED MOLES
  OR MASS)
• IF GIVEN MASS, OF MOLES OF GIVEN MUST BE
  CALCULATED BY THE EQUATION
• 
  MASS
• OF MOLS
  MOLAR MASS
• 3. FROM EQUATION CALCULATE MOLE RATIOS
• 4. USE MOLE RATIOS TO FIND THE OF MOLS
  REQUIRED.(Use Coefficients)
• 5. IF MASS OF REQUIRED CALCULATE USING THE SAME
  EQUATION
• MASS
• OF MOLS MOLAR MASS OR MASS OF
  MOLS x MOLAR MASS

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CONVERSION FACTORS

• MOLAR MASS AS CONVERSION FACTOR ARE
• A 102g B) I MOL Al2O3
• 1 MOL Al2O3 102g
• C) 27g D) 1 MOL Al
• 1 MOL Al 27g
• E) ___32g__ F) 1 MOL OF O2
• 1 MOL OF O2 32g

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CONVERSION FACTORS

• 2Al2O3 -gt 4Al 3O2
• A) 2 MOLES OF ALUMINUM OXIDE OR B) 4
  MOLES OF Al
• 4 MOLES OF ALUMINUM
  2 MOLES OF Al2O3
• C) 4 MOLS OF Al OR
  D) 3 MOLS OF O2
• 3 MOLS OF O2
  4 MOLS OF Al
• E) 2 MOLS OF Al203 OR
  F) 3 MOLS OF O2
• 3 MOLS OF O2
  2 MOLS OF Al2O
• THEREFORE IF GIVEN 13 MOLES OF Al2O3, HOW MANY
  MOLS OF Al WILL BE PRODUCED.
• 13 MOLES OF Al2O3 X 4 MOLS OF Al
  26 MOLS OF Al
• 
  2 MOLS OF Al2O3

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• THEREFORE, IF YOU WANTED THE MASS OF THE ALUMINUM
  PRODUCED IN THE PREVIOUS PROBLEM, YOU CALCULATE
  THE FOLLOWING
• 26 MOLS OF Al x 27g Al 702g OF
  Al
• 1 MOL OF Al

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9.2 IDEAL STOICHIOMETRY CALCULATIONS

• ASSUME COMPLETE CONVERSION OF ALL REACTANTS
• INTO PRODUCTS.
• 1) MOLE - MOLE CALCULATION -
• MOLES OF SUBSTANCE A -gt MOLS OF B
• MOLES OF A x MOLE RATIO B -gt MOLS OF B
• A
• 2) MOLE - MASS CALCULATION
• MOLES OF A -gt MOLS OF B -gt MASS OF B
• MOLS OF A x MOLE RATIO B x MOLAR MASS OF B MASS
  OF B
• A

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• 3) MASS - MOLE CALCULATION
• MASS OF A -gt MOL OF A -gt MOLS OF B
• MASS OF A x MOLE RATIO OF B -gt
  MOLS OF B
• MOLAR MASS OF A A
• 4) MASS - MASS CALCULATION
• Mass A ?Mols A ? Mols B ? Mass B
• MASS OF A X MOLE RATIO B -gt MOLS B X
  Molar Mass B -gtMass B
• MOLAR MASS OF A A