visualizing a chemical reaction
DESCRIPTION
Visualizing a Chemical Reaction. 2. 2. Na + Cl 2 NaCl. 10. 5. 10. 10. ?. 10. 5. ___ mole Na. ___ mole Cl 2. ___ mole NaCl. Formation of Ammonia. Ratio of eggs to cookies. Proportional Relationships. 2 1/4 c. flour - PowerPoint PPT PresentationTRANSCRIPT
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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
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
• Stoichiometry– mass relationships between substances in a chemical
reaction– based on the mole ratio
• Mole Ratio– indicated by coefficients in a balanced equation
2 Mg + O2 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 reactions
Precipitation reactions
Acid-BaseReactions
Oxidation-ReductionReactions
Combustion Reactions
Summary of Classes of Reactions
Chemical reactions
Precipitation reactions
Acid-BaseReactions
Oxidation-ReductionReactions
Combustion Reactions
Decomposition reactions
(Products are elements.)
Synthesis reactions
(Reactants are elements.)
Summary of Classes of Reactions
Chemical reactions
Precipitation reactions
Acid-BaseReactions
Oxidation-ReductionReactions
Combustion Reactions
Decomposition 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