The document discusses balancing chemical equations by ensuring that the same number and type of atoms appear on both sides of the reaction arrow. It provides examples of balancing a variety of chemical equations involving reactants like Mg, HCl, SO2, and products like MgCl2, SO3, NO2. Students are encouraged to practice balancing many different types of equations involving metals, nonmetals, acids, bases, and other chemicals.

1. Balancing Equations

2. Yay, balancing equations! The law of conservation of matter tells us that during a chemical change no material is created or destroyed. This means that all of the atoms that appear on the reactant side of the equation must also appear on the products side. Now that we are using symbols the equations must be balanced . Let us see what balancing involves. Consider the following equation: NaOH + Pb(NO3)2  Pb(OH)2 + NaNO3 1 sodium 1 lead 1 lead 1 sodium 1 oxygen 2 nitrogen 2 oxygen 1 nitrogen 1 hydrogen 6 oxygen 2 hydrogen 3 oxygen

3. You must NEVER try to change a formula in order to balance an equation. 2NaOH + Pb(NO3)2  Pb(OH)2 + NaNO3 2 sodium 1 lead 1 lead 2 sodium 2 oxygen 2 nitrogen 2 oxygen 2nitrogen 2 hydrogen 6 oxygen 2 hydrogen 6 oxygen

4. Try to balance these equations Mg + HCl  MgCl 2 + H 2 Mg + O 2  MgO SO 2 + O 2  SO 3 KClO 3  KCl + O 2

5. All we need now is plenty of practice. NO + O 2  NO 2 Fe + HCl  FeCl 2 + H 2 NaHCO 3  Na 2 CO 3 + CO 2 + H 2 O Al + O 2  Al 2 O 3 FeS + HCl  FeCl 2 + H 2 S

6. More? C 2 H 6 + O 2  CO 2 + H 2 O Mg + CO 2  MgO + C Ca(OH) 2 + CH 3 COOH  Ca(CH 3 COO) 2 + H 2 O KOH + H 2 SO 4  K 2 SO 4 + H 2 O Pb(NO 3 ) 2 + ZnCl 2  Zn(NO 3 ) 2 + PbCl 2

7. And some more! AlCl 3 + NaOH  Al(OH) 3 + NaCl Ca + H 2 O  Ca(OH) 2 + H 2 Ca(NO 3 ) 2 + (NH 4 ) 2 CO 3  CaCO 3 + NH 4 NO 3 K 3 PO 4 + Fe(NO 3 ) 2  Fe 3 (PO 4 ) 2 + KNO 3

8. More challenging ones C 12 H 22 O 11 + O 2  CO 2 + H 2 O Mg(HCO 3 ) 2  MgO + CO 2 + H 2 O MgCO 3 + H 3 PO 4  Mg 3 (PO 4 ) 2 +H 2 O + CO 2 S + Fe 2 O 3  Fe + SO 2 Cu + HNO 3  Cu(NO 3 ) 2 +NO 2 + H 2 O

9. MnO 2 + HCl  MnCl 2 + H 2 O + Cl 2 FeS + O 2  Fe 2 O 3 + SO 2 CH 3 OH + O 2  H 2 O + CO 2 NH 3 + O 2  N 2 + H 2 O NO 2 + H 2 O  HNO 3 + NO