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Balancing Chemical Equations. Rules:. 1. LEARN THESE DIATOMIC MOLECULES : O 2 H 2 N 2 F 2 Cl 2 Br 2 I 2 2. The same number of atoms of each element appearing in reactants must appear in the products .
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Rules: 1. LEARN THESE DIATOMIC MOLECULES: O2 H2 N2 F2 Cl2 Br2 I2 2. The same number of atoms of each element appearing in reactants must appear in the products. 3. The subscripts of a formula cannot be changed to balance the equation. Each compound must retain its stableness via oxidation states. 4. Choose compound with greatest number of atoms first. 5. Balance by placing necessary coefficients in front of entire molecules. NO SUBSCRIPT CHANGES!
Rules cont. 6. Be certain each side of equation has same number of atoms of each type. 7. Make sure coefficients are in lowest whole number ratios. 8. Polyatomic ions usually stay intact, but multiple polyatomic ions may be separated. 9. (aq.) stands for aqueous which is Latin for water solution: (g) gas (l) liquid (s) solid (c) crystalline solid
More Rules: • means “yields” and shows direction of action • ∆ above arrow shows heat has been added • shows reaction is reversible • MINOH: try Metals first, then Ions, then Nonmetals, and Oxygen, then Hydrogen last
Sample Problem: C8H18 + O2 CO2 + H2O C8H18 + O2 __ CO2 + __ H2O C8H18 + __ O2 __ CO2 + __ H2O __ C8H18 + __ O2 __ CO2 + __ H2O
Practice Problems: H2CrO4 + AgNO3 Ag2CrO4 + HNO3 (aq) (aq) (s) (aq) Chromic + Silver Silver + Nitric Acid Nitrate Chromate Acid 1, 2, 1, 2 Double displacement
Problem # 6 Cu(NO3)2 CuO + NO2 + O2 (aq) (s) (g) (g) Copper (II) Copper (II) + Nitrogen + Oxygen Nitrate Oxide Dioxide Gas 2, 2, 4, 1 Decomposition
Problem # 14 AlBr3 + Cl2 AlCl3 + Br2 (aq) (g) (aq) (g) Aluminum + Chlorine Aluminum + Bromine Bromide Gas Chloride Gas 2, 3, 2, 3 Single Displacement
Problem # 2 P4 + O2 + H2O H3PO4 (s) (g) (aq) (aq) Phosphorus + Oxygen + Water Phosphoric (free) gas acid 1, 5, 6, 4 Synthesis
Problem # 20 sodium permanganate + sulfuric acid sodium sulfate + manganese (VII) oxide + water NaMnO4 + H2SO4 Na2SO4 + Mn2O7 + H2O (aq) (aq) (aq) (s) (l) 2, 1, 1, 1, 1 Double Displacement
Problem # 3 Th(NO3)4 + K3PO4 Th3(PO4)4 + KNO3 (aq) (aq) (s) (aq) Thorium + Potassium Thorium + Potassium Nitrate Phosphate Phosphate Nitrate 3, 4, 1, 12 Double Displacement
Problem # 22 sulfur trioxide + nitric acid sulfuric acid + dinitrogen pentoxide SO3 + HNO3 H2SO4 + N2O5 (g) (aq) (aq) (g) 1, 2, 1, 1 Double Displacement
Problem # 7 NH4NO3 + Ca(OH)2 Ca(NO3)2 + NH3 + H2O (aq) (aq) (aq) (g) (l) Ammonium + Calcium Calcium + Ammonia + water Nitrate Hydroxide Nitrate 2, 1, 1, 2, 2 Double Displacement
Missing Products sodium chloride + potassium iodide NaCl + KI ________ + _________ (aq) (aq) (?) (?) Does a reaction take place?
Balancing Wars Problem # 1 CuSO4 + H3PO4 _____ + ______ (aq) (aq) • 3, 1, 2, 1 • 3, 1, 1, 3 • 2, 3, 3, 2 • 3, 2, 1, 3 • 2, 3, 3, 1 ((D)) Copper (II) + Phosphoric Copper (II) + Sulfuric Sulfate Acid Phosphate Acid
Balancing Wars Problem # 2 Mg(OH)2 + H3PO4 _____ + ______ (aq) (aq) • 1, 1, 1, 1 • 3, 2, 1, 3 • 2, 3, 1, 6 • 2, 3, 1, 1 • 3, 2, 1, 6 ((E.)) Magnesium + Phosphoric Magnesium + Water Hydroxide Acid Phosphate
Balancing Wars Problem # 3 CuCl2 + Na3PO4 _____ + ______ (aq) (aq) • 1, 2, 1, 2 • 2, 3, 1, 6 • 2, 3, 1, 1 • 3, 2, 1, 6 • 1, 1, 1, 1 ((D)) Copper (II) + Sodium Copper (II) + Sodium Chloride Phosphate Phosphate Chloride
Balancing Wars Problem 4 Potassium + Nickel (II) _____ + ______ Permanganate Nitrate • 2, 1, 2, 1 • 2, 1, 3, 1 • 1, 2, 1, 2 • 1, 2, 1, 3 • 1, 1, 1, 1 ((A)) KMnO4 + Ni(NO3)2 KNO3 + Ni(MnO4)2
Balancing Wars Bonus Problem KMnO4 + Na2C2O4 + H2SO4 K2SO4+ Na2SO4+ MnSO4+ CO2+ H2O Balance this equation and show your atom inventory and earn a grade pass.