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Visualizing a Chemical Reaction
Na + Cl2 NaCl
___ mole Cl2 ___ mole NaCl___ mole Na
2
10 5 10
2
10 5 10
Formation of Ammonia
Proportional Relationships
I have 5 eggs. How many cookies can I make?
3/4 c. brown sugar1 tsp vanilla extract2 eggs2 c. chocolate chipsMakes 5 dozen cookies.
2 1/4 c. flour1 tsp. baking soda1 tsp. salt1 c. butter3/4 c. sugar
5 eggs
2 eggs= 12.5 dozen cookies
Ratio of eggs to cookies
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
150 cookies5 dozen
ConversionFactor
Proportional Relationships
• StoichiometryStoichiometry– mass relationships between substances in a chemical
reaction– based on the mole ratio
• Mole RatioMole Ratio– indicated by coefficients in a balanced equation
2 Mg + O2 Mg + O22 2 MgO 2 MgO
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
Stoichiometry Steps1. Write a balanced equation.2. Identify known & unknown.3. Line up conversion factors.
– Mole ratio - moles moles– Molar mass - moles grams– Molarity - moles liters soln– Molar volume - moles liters gas
Core step in all stoichiometry problems!!
– Mole ratio - moles moles
4. Check answer.Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
1 mol of a gas=22.4 Lat STP
Molar Volume at STP
Standard Temperature & Pressure0°C and 1 atm
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
Molar Volume at STP
Molar Mass(g/mol)
6.02 1023
particles/mol
MASSIN
GRAMSMOLES
NUMBEROF
PARTICLES
LITERSOF
SOLUTION
Molar Volume (22.4 L/mol)
LITERSOF GASAT STP
Molarity (mol/L)
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
Stoichiometry Problems• How many moles of KClO3 must decompose
in order to produce 9 moles of oxygen gas?
9 mol O2 2 mol KClO3
3 mol O2
= 6 mol KClO3
2KClO3 2KCl + 3O2 ? mol 9 mol
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
1. 2 Sb + 3 Cl2 2 SbCl3
2. 2 Mg + O2 2 MgO
3. CaCl2 Ca + Cl2
4. 2 NaClO3 2 NaCl + 3 O2
5. Fe + 2 HCl FeCl2 + H2
6. CuO + H2 Cu + H2O
7. 2 Al + 3 H2SO4 Al2(SO4)3 + 3 H2
7.5 mol
1. 2 Sb + 3 Cl2 2 SbCl3
How many moles of chlorine gas are required to react with 5 moles of antimony?
5 mol x mol
x mol Cl2 = 5 mol Sb2 mol Sb
3 mol Cl2 = 7.5 mol Cl2
How many moles of SbCl3 are produced from 5 moles of antimony and excess Cl2?
x mol SbCl3 = 5 mol Sb2 mol Sb
2 mol SbCl3 = 5 mol SbCl3
excess x mol
How many moles of SbCl3 are produced from 7.5 moles of Cl2 and excess Sb?
x mol SbCl3 = 7.5 mol Cl23 mol Cl2
2 mol SbCl3 = 5 mol SbCl3
25 mol
3x mol
=
2 x = 15x = 7. 5 mol
excess
2. 2 Mg + O2 2 MgO
How many moles of magnesium oxide are produced from the burning of 10 mol of Mg?
x mol MgO = 10 mol Mg2 mol Mg
2 mol MgO= 10 mol MgO
x mol10 mol
How many liters of oxygen are needed to burn 10 mol of Mg?
x L O2 = 10 mol Mg2 mol Mg
1 mol O2 = 5 mol O2
Assume 1 mol O2 = 22.4 L
1 mol O2
22.4 L O2 = 112 L O2
x L
x L O2 = 10 mol Mg2 mol Mg
1 mol O2
1 mol O2
22.4 L O2 = 112 L O2
3. CaCl2 Ca + Cl2
How many moles of calcium metal are produced from the decomposition of 8 mol of calcium chloride?
x mol Ca = 8 mol CaCl21 mol CaCl2
1 mol Ca= 8 mol Ca
x mol8 mol
How many moles of calcium metal and chlorine gas are produced from the decomposition of 8 mol of calcium chloride?
x mol Cl2 = 8 mol CaCl21 mol CaCl2
1 mol Cl2 = 8 mol Cl2
and chlorine gas
Pb2+NO3
1–
Na1+ I1–
Ions in Aqueous Solution
Pb(NO3)2(s) Pb(NO3)2(aq)
Pb2+(aq) + 2 NO31–(aq)
addwater
NaI(s)
+ H2O(l)
dissociation:
+ H2O(l)
Na1+(aq) + I1–(aq)
Mix them and get…
Balance to get overall ionic equation…
Cancel spectator ions to get net ionic equation…
Print Copy of Lab
Print Copy of Lab
NaI(aq)
NO31–
Pb2+
NO31–
NO31–
in solution
Na1+ I1–
Mix them and get…
Pb2+(aq) + 2 NO31–(aq) + 2 Na1+(aq) + 2 I1–(aq) PbI2(s) + 2 NO3
1–(aq) + 2 Na1+(aq)
Pb2+(aq) + 2 I1–(aq) PbI2(s)
Pb(NO3)2(aq) + 2 NaI(aq) PbI2(s) + 2 NO31–(aq) + 2 Na1+(aq)
Balance to get overall ionic equation…
Cancel spectator ions to get net ionic equation…
SolubilityChart
solid
in solution
Pb2+NO3
1–
Na1+ I1–
NO31–
Na1+ I1–
Pb2+
NO31–
Na1+
I1–
NO31–
Na1+
I1–
PbI2 + NaNO3(s) (aq)
Ba2+
OH1–
OH1–
NO31–
NO31–
Mix together Zn(NO3)2(aq) and Ba(OH)2(aq):
Zn2+(aq) + 2 NO31–(aq) Ba2+(aq) + 2 OH1–(aq)
Ba(OH)2(aq)Zn(NO3)2(aq)
Balance to get overall ionic equation…
Zn2+
Zn(NO3)2(aq) + Ba(OH)2(aq) Zn(OH)2(s) + 2 NO31–(aq) + Ba2+(aq)
Zn2+(aq) + 2 NO31–(aq) + Ba2+(aq) + 2OH1–(aq) Zn(OH)2(s) + 2 NO3
1–(aq) + Ba2+(aq)
Mix them and get…
Zn2+(aq) + 2 OH1–(aq) Zn(OH)2(s)
Cancel spectator ions to get net ionic equation…
SolubilityChart
Ba(NO3)2 and Zn(OH)2(aq) (ppt)
(NH4)3PO4 + Mg(OH)2 Mg3(PO4)2 NH4OH?
ammonium phosphate magnesium hydroxide magnesium phosphate ammonium hydroxide
NH41+ OH1-
+ 62 3
Now you try…
AlCl3 + Li2CO3 Al2(CO3)3 + LiCl32 6
Al2(SO4)3(aq) + 6 NH4OH(aq) 2 Al(OH)3 + 3 (NH4)2SO4
2 Al3+(aq) + 3 SO42-(aq) + 6 NH4
1+(aq) + 6 OH1-(aq) 2 Al(OH)3(ppt) + 6 NH41+(aq) + 3 SO4
2-(aq)
2 Al3+(aq) + 6 OH1-(aq) 2 Al(OH)3(ppt)
Net Ionic Equation
Identify the spectator ions and write a net ionic equation when an aqueous solution of aluminum sulfate is mixed with aqueous ammonium hydroxide.
sulfate + hydroxide aluminum ammoniumaluminum ammonium aluminum hydroxide ammonium sulfate+Al3+ SO4
2- NH41+ OH1- Al3+ SO4
2-NH41+OH1-
(ppt) (aq)
“spectator ions”
Meaning of Coefficients
2 Na + Cl2 2 NaCl2 g sodium 1 g chlorine 2 g sodium chloride+ =
2 mol sodium 1 mol chlorine 2 mol sodium chloride
(2 mol Na) x (23 g/mol) (1 mol Cl2) x (71 g/mol) (2 mol NaCl) x (58.5 g/mol)
46 g 71 g 117 g
117 g
2 atoms Na 1 molecule Cl2 2 molecules NaCl
Classes of Reactions
Chemical reactionsChemical reactions
Precipitation reactions
Precipitation reactions
Acid-BaseReactionsAcid-BaseReactions
Oxidation-ReductionReactions
Oxidation-ReductionReactions
Combustion Reactions
Combustion Reactions
Summary of Classes of Reactions
Chemical reactionsChemical reactions
Precipitation reactions
Precipitation reactions
Acid-BaseReactionsAcid-BaseReactions
Oxidation-ReductionReactions
Oxidation-ReductionReactions
Combustion Reactions
Combustion Reactions
Decomposition reactions
(Products are elements.)
Decomposition reactions
(Products are elements.)
Synthesis reactions
(Reactants are elements.)
Synthesis reactions
(Reactants are elements.)
Summary of Classes of Reactions
Chemical reactionsChemical reactions
Precipitation reactions
Precipitation reactions
Acid-BaseReactionsAcid-BaseReactions
Oxidation-ReductionReactions
Oxidation-ReductionReactions
Combustion Reactions
Combustion Reactions
Decomposition reactions
Decomposition reactions
Synthesis reactions Synthesis reactions
IONIC BONDING: Formation of Magnesium Chloride
Mg Mg2+
Cl
Cl
Cl
Cl
Loses 2e- Each gains 1e- One magnesium ion Two chloride ions Mg2+ Cl1-
[(2+) 2 (1-) = 0]
MgCl2 magnesium chloride
Mg2+
IONIC BONDING: Formation of Magnesium Chloride
Mg Mg2+
Cl
Cl
Cl
Cl
Loses 2e- Each gains 1e- One magnesium ion Two chloride ions Mg2+ Cl1-
[(2+) 2 (1-) = 0]
MgCl2 magnesium chloride
Resources - Chemical Equations and Reactions
Worksheet - vocabularyWorksheet - vocabularyWorksheet – Balancing Chemical EquationsWorksheet – Balancing Chemical Equations
Lab – Ions in SolutionLab – Ions in Solution
Worksheet – Chemical Word EquationsWorksheet – Chemical Word EquationsWorksheet – Quantitative Relationships in Chem. Eqns.Worksheet – Quantitative Relationships in Chem. Eqns.Worksheet – Chemical Equations (paragraph)Worksheet – Chemical Equations (paragraph)Worksheet – Real Life ChemistryWorksheet – Real Life ChemistryWorksheet – Balancing Equations (visual) Worksheet – Balancing Equations (visual) Worksheet - Worksheet -
Outline (general)(general)
Textbook - questionsTextbook - questions