Balancing Equations Balancing, Writing, and Naming Equations

Balancing Equations

Law of Conservation of Matter: Law of Conservation of Matter: In a chemical reaction, matter can be neither created nor destroyed. In a chemical reaction, matter can be neither created nor destroyed. In a chemical reaction, the amount of reactants equal the amount of products. In a chemical reaction, the amount of reactants equal the amount of products.

Balancing Equations Paraphrased: Law of Conservation of Atoms: Law of Conservation of Atoms: The number of atoms of each type of element must be the same on each side of the equation. The number of atoms of each type of element must be the same on each side of the equation.

Chemical Equations

Balancing Chemical Equations Draw a reactant/ product table, listing each atom type. Draw a reactant/ product table, listing each atom type. Count each atom on both sides of equation. Count each atom on both sides of equation. Balance by trial & error (one atom at a time) until you have the same # of atoms of each element on both sides of the equation. Balance by trial & error (one atom at a time) until you have the same # of atoms of each element on both sides of the equation. Balance by adding coefficients, not subscripts. Balance by adding coefficients, not subscripts. RP Zn11 H12 Cl12 Zn(s) + _HCl(aq)  ZnCl 2 (aq) + H 2 (g)

Balancing Equations Hydrogen + oxygen water Hydrogen + oxygen water H 2 + O 2 H 2 O H 2 + O 2 H 2 O

Balancing Equations N 2 + H 2 NH 3 N 2 + H 2 NH 3 Nitrogen + hydrogen ammonia Nitrogen + hydrogen ammonia

Balancing Equations Ca 3 (PO 4 ) 2 + H 2 SO 4 CaSO 4 + H 3 PO 4 Ca 3 (PO 4 ) 2 + H 2 SO 4 CaSO 4 + H 3 PO 4

Balancing Equations Cu + H 2 SO 4 Cu + H 2 SO 4 CuSO 4 + H 2 O + SO 2 CuSO 4 + H 2 O + SO 2

NaOH + CaBr 2  Ca(OH) 2 + NaBr NaOH + CaBr 2  Ca(OH) 2 + NaBr

C 2 H 6 + O 2  CO 2 + H 2 O C 2 H 6 + O 2  CO 2 + H 2 O

Writing and Naming Write the corresponding formula equation and then balance the equation. Nickel + hydrochloric acid Nickel + hydrochloric acid Nickel(II) chloride + hydrogen Nickel(II) chloride + hydrogen

Writing and Naming Write each formula independently. Write each formula independently. Ignore the rest of the equation. Ignore the rest of the equation. Balance the equation after writing the formulas. Balance the equation after writing the formulas. Ni + HCl NiCl 2 + H 2 Ni + HCl NiCl 2 + H 2 Ni + 2HCl NiCl 2 + H 2 Ni + 2HCl NiCl 2 + H 2

Writing and Naming Remember the diatomic elements: H 2, N 2, O 2, F 2, Cl 2, Br 2, and I 2. Remember the diatomic elements: H 2, N 2, O 2, F 2, Cl 2, Br 2, and I 2.

Writing and Naming Balance the formula equation. Write the word equation. Cu + H 2 SO 4 Cu + H 2 SO 4 CuSO 4 + H 2 O + SO 2 CuSO 4 + H 2 O + SO 2

Writing and Naming Cu + 2H 2 SO 4 Cu + 2H 2 SO 4 CuSO 4 + 2H 2 O + SO 2 CuSO 4 + 2H 2 O + SO 2 Write the names: Cu by itself is just copper. Copper(I) or copper(II) would be incorrect. H 2 SO 4 should be named as an acid. Sulfuric acid

Writing and Naming CuSO 4 has a SO 4 2- group so Cu must be 2+. Some metals must have Roman Numerals. Copper(II) sulfate CuSO 4 has a SO 4 2- group so Cu must be 2+. Some metals must have Roman Numerals. Copper(II) sulfate H 2 O is known as water. H 2 O is known as water. SO 2 is a nonmetal compound. Its name is either sulfur dioxide or sulfur(IV) oxide. SO 2 is a nonmetal compound. Its name is either sulfur dioxide or sulfur(IV) oxide.

Writing and Naming Copper + sulfuric acid  Copper(II) sulfate + water + sulfur dioxide Cu + 2H 2 SO 4 Cu + 2H 2 SO 4 CuSO 4 + 2H 2 O + SO 2 CuSO 4 + 2H 2 O + SO 2

Balancing Equations Practice! Practice!

Balancing chemical equations 1. _ Na + Cl 2 → _ NaCl 2. _ Fe(s) + _ Cl 2 (g) → _ FeCl 3 3. _ Ag 2 O → _ Ag + O 2 4. _ CuCl 2 + _ Al → _ AlCl 3 + _ Cu 5. _ AgNO 3 + MgCl 2 → _ AgCl + Mg(NO 3 ) 2

Types of Chemical Rxns Classifying reactions Classifying reactions There are 5 general types of reactions There are 5 general types of reactions Combustion Combustion Synthesis ( Combination) Synthesis ( Combination) Decomposition Decomposition Single-replacement (single-displacement) Single-replacement (single-displacement) Double-replacement (double-displacement) Double-replacement (double-displacement) Not all chemical reactions fit uniquely into only one of these classes Not all chemical reactions fit uniquely into only one of these classes Sometimes, one rxn may fit 2 or 3 different types Sometimes, one rxn may fit 2 or 3 different types