Balancing Equations

Alabama Course of Study

• 4.) State the law of conservation of matter.

• 4.1Balancing chemical equations by adjusting coefficients

Chemical Equations

• Chemical Equation- representation of a chemical reaction that uses symbols to show the relationship between the reactants and products– Reactants- what is put into a reaction– Product- what forms after a reaction

occurs

An example

•C +o2 =co2• Reactants Product

Law of Conservation of Mass

• Law of mass of energy- Mass is neither created nor destroyed and both sides of the equation must be equal

How many atoms are in each Compound?

• H2CO3 =___H ___C ___O

• H20 = ___ H ___0

• HCl = ___H ___ Cl

• ZnCl2 = ___Zn ___Cl

• AgNO3 =___ Ag ___N ___O

• FeCl2 = ___Fe ___Cl

How many atoms are in each Compound?

• 2H2CO3 =___H ___C ___O

• 3H20 = ___ H ___0

• 4HCl = ___H ___ Cl

• 2ZnCl2 = ___Zn ___Cl

• 3AgNO3 =___ Ag ___N ___O

• 4FeCl2 = ___Fe ___Cl

Rules to balancing equations

• Rule 1- the superscript or the two in co2 cannot be changed

• Rule 2- You can add a coefficient or the three in 3co2

• Rule 3- the atoms on both sides must be equal

Example

More problems

•Na + Cl2 = NaCl•Mg + N2 = Mg3N2

•2KI + Cl2 = KCl + I2•FeS +HCl = FeCl2 + H2S•Na + O2 = Na20•Ag3N = Ag + N•P4 + O2 = P2O5

Different kinds of chemical reactions

• Synthesis reaction- two or more substances form to make one new compound

• 2Na + Cl2 = 2NaCl

• 1 + 2 = 3

• C + 02 = C02

Decomposition

• Decomposition- single compound is broken down into two or more compounds

• H2CO3 = H20 + C02

• 3 = 1 + 2

Single Displacement Reactions

• Single displacement- one element takes the place of another element

• Zn + 2HCl = ZnCl2 + H2

• 1 + 2x3 = 1x3 + 2

Double-displacement

• Double- displacement- two substances change places with each other

• NaCl + AgF = NaF + AgCl• 1 X2 + 3X4 = 1X4 + 3 X 2