Balancing Equations

Balancing Equations

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

Balancing Equations Paraphrased: Law of Conservation of Atoms: 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. 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 adding coefficients, not subscripts. Zn(s) + _HCl(aq)  ZnCl2(aq) + H2(g) R P Zn 1 H 2 Cl

Hydrogen + oxygen water Balancing Equations Hydrogen + oxygen water H2 + O2 H2O

Nitrogen + hydrogen ammonia Balancing Equations N2 + H2 NH3 Nitrogen + hydrogen ammonia

Balancing Equations Ca3(PO4)2 + H2SO4 CaSO4 + H3PO4

Balancing Equations Cu + H2SO4 CuSO4 + H2O + SO2

NaOH + CaBr2  Ca(OH)2 + NaBr

C2H6 + O2  CO2 + H2O

Key to Balancing Equations Practice! Trial & Error!!!

Balancing chemical equations _ Na + _Cl2 → _ NaCl _ Fe(s) + _ Cl2(g) → _ FeCl3 _ Ag2O → _ Ag + _O2 4. _ CuCl2 + _ Al → _ AlCl3 + _ Cu 5. _ AgNO3 + _MgCl2 → _ AgCl + _Mg(NO3)2

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