Balancing Equations 2017 filled in.notebook
January 30, 2017
Aim: To show a conservation of mass by balancing the quantity of atoms on each side of a chemical equation.
Jan 22­3:51 PM
Conservation of Matter
Law of conservation of matter: Matter cannot be created
or destroyed but is conserved.
• Mass, charge, and energy are conserved in chemical
reactions.
• To show a conservation of matter , the number of each
type of atom on both sides of an equation MUST BE EQUAL
Dec 30­7:00 PM
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Balancing Equations 2017 filled in.notebook
January 30, 2017
Structure of an Equation
Reactants
Products
H2 + Cl2
2 HCl
1 molecule of hydrogen reacts with 1
molecule of chlorine to yield 2 molecules
of hydrogen chloride
Dec 30­7:00 PM
To balance an equation:
1. Take inventory of all atoms on both sides of the equation.
2. Balance using coefficients to adjust the number of molecules of each substance.
3. NEVER EVER change subscripts.
4. Start on the side with the lowest number of atoms first.
5. If a polyatomic ion remains intact on both sides of an equation, it can be treated as one whole piece.
6. Always use the lowest whole number ratio of coefficients.
H
O
H
H2 + O2 H2 O
H
2 atoms hydrogen, 2 atoms oxygen
NOT BALANCED
2 atoms hydrogen, 1 atom oxygen
O
O
H
H
H
O
H
H
2 H2 + O2 H
2 2O
BALANCED
4 atoms hydrogen
4 atoms hydrogen
2 atoms oxygen
2 atoms oxygen
Dec 30­7:00 PM
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Balancing Equations 2017 filled in.notebook
January 30, 2017
Example #2
Tic­Tac Toe
MINOH
AgNO3 + MgCl2 AgCl + Mg(NO3)2
1 Ag atom
1 Ag atom
1 nitrate ion (NO3)
1 Mg atom
NOT BALANCED
2 nitrate ions (NO3)
1 Mg atom
1 Cl atoms
2 Cl atoms
2
2 AgNO3 + MgCl2 AgCl + Mg(NO
3 )2
2 Ag atoms
2 Ag atoms
2 nitrate ions (NO3)
2 nitrate ions (NO3)
1 Mg atom
BALANCED
2 Cl atoms
1 Mg atom
2 Cl atoms
Dec 30­7:00 PM
Example #3
Tic­Tac Toe
MINOH
Na + O2 Na2O
4 Na +
O2 2 Na2O
Dec 30­7:00 PM
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Balancing Equations 2017 filled in.notebook
January 30, 2017
Example #4
N2 + H2 NH3
N2 + 3 H2 2NH3
Dec 30­7:00 PM
Example #5
Ca3(PO4)2 + H2SO4
CaSO4 + H3PO4
HCl +
Ca3(PO4)2 + H
3 2SO4
2 3PO4
3CaSO4 + H
Dec 30­7:00 PM
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Balancing Equations 2017 filled in.notebook
January 30, 2017
Example #6
P + O2 P4O10
4 P + 5 O2 P4O10
Dec 30­7:00 PM
Practice
7. NaCl + F2
NaF
2 NaCl + F2
+ HCl
2 NaF + HCl
2
8. AgNO3 + MgCl2
AgCl + Mg(NO3)2
2 AgNO3 + MgCl2
AgCl
+ Mg(NO3)2
2
Dec 30­7:00 PM
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