Todays Tasks

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Todays Tasks

• Naming Acids (finish cp. 2)
• Mole calculations
• Balancing Reactions

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Friday

• Ionic Compounds
• Covalent Compounds
• Polyatomic Ions

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Chapter 2Atoms Molecules and Ions
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Which of the following are acids? NH4NO3 CaCO3
H2CO3 HCl NaCl NaHCO3
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Name the following acids H2CO3 HCl
HNO3HNO2 HCH3OO H3PO4
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Name the followingIs it an acid?
NaOH
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Chapter 3Stoichiometry
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Nobel Prize in Chemistry2007Gerhard Ertl
Germany

• Chemical processes on solid Surfaces

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Fertilizer

• Haber-Bosch process
• N2 3H2 ? 2NH3
• First key step to making fertilizer

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N N and H-H bonds break on Iron surface

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N-H bonds form, NH3 forms and leaves metal
surface
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Balanced Reaction

• N2 3H2 ? 2NH3

What does this tell you?
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Balanced Reaction

• N2 3H2 ? 2NH3
• 1 molecule of N2 reacts with 3 molecules of H2 to
  make 2 molecules of NH3

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What is a Mole?
A mole is an amount
Ex. A pair 2 things A dozen 12 things A
billion 1 x 109 things A mole 6.022x1023
things

• Avogadros number (N) 6.022 x 1023

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Molar Mass
What is the mass of 1 carbon atom?
12C 12 amu exactly

• amu atomic mass units
• 1 amu 1.66 x 10-24 g

Molar Mass the mass of 1 mole of a compound
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Molar Mass
What is the molar mass carbon?
Molar Mass the mass of 1 mole of a compound
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Molar Mass
6
C
12.01
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Calculate the molar mass ofmethanecalcium
phosphate
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Calculate the volume (in mL) of one mole water.
Density of water 1g/mL
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Balancing Chemical Reactions
N2 H2 ? NH3Write the balanced reaction
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Balancing Chemical Reactions
Aluminum metal reacts with oxygen to produce
aluminum oxide.Write the balanced reaction
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Balancing Chemical Reactions
C2 H2OH O2 ? CO2 H2 OWrite the balanced
reaction
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Limiting reagent problems

• 2 pieces bread 1 piece ham ? 1 sandwich
• Have 14 pieces of bread, 8 pieces of ham
• How many sandwiches can we make?
• What is the limiting item?
• What do you have left over?

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Limiting Item?

• 2 pieces bread 1 piece ham ? 1 sandwich
• Have 500 g of bread and 300 grams of ham
• How many sandwiches can we make?
• What must we do first?

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Stoichiometry

• 4 Al (s) 3 O2 (g) ? 2 Al2O3 (s)
• Have 5.6 mol Al and 3.1 mol O2
• How much Al2O3 produced?
• How much Al left over?

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Stoichiometry

• Photosynthesis Where?

H-O-H ?
OCO
OO
Carbohydrate C6(H2O)6 C6H12O6
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Demo

• Van Helmont expt with tree ? gain in mass due
  to H2O?
• Priestly studied gases showed difference
  between CO2 and H2O
• Balanced eqn for photosynthesis took 200 yr !!

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Stoichiometry

• Photosynthesis
• 6CO2 6H2O ? C6H12O6 6O2
• 100 g ? g

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•  
• 
  
  

Percent Yield and Theoretical Yield
N2 3H2 ? 2NH3
a)  If if we combine 100 g of N2 and 30 g of H2
which is the limiting reagent (the reactant that
is used up first)?
b)  How much NH3
is produced (in grams) assuming the reaction goes
to completion? This is called the theoretical
yield.











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• c)  Say we did an experiment where we combined 
  100 g of N2 and 30 g of H2 and the reaction
  produces 105.7 g of NH3.  Calculate the percent
  yield.