A 2 + 3BA2B3A2B3 Balancing Equations can be fun yet tough! This presentation will provide you some helpful tricks.

Chemical Reactions Chemical Reaction (rxn): Atom arrangement is changed. (Bonds are formed or broken) Chemical Equation: Shorthand notation describing what has taken place in a rxn.

Chemical Reactions Reactants: Beginning substances Products: Ending substances Reactants Products Yields

Chemical Reactions Phases of Matter: Solid (s) Liquid (l) Gas (g) Aqueous Solution (aq) -solids dissolved in water solution

Chemical Reactions Catalyst: Speed up a reaction, but are not used up in the reaction & are shown above the arrow Reactants Products A + B AB

Chemical Reactions Law of the Conservation of Matter: Matter is not created nor destroyed, but conserved in any chemical reaction Must have same # of elements on both sides of the reaction.

Chemical Reactions Coefficients: Numbers placed in front of a formula, used to balance HgO Hg + O 2 Reactants Products 22

Chemical Reactions H 2 O (l) H 2 + O 2 Notice that as it stands, we have one oxygen on the reactants side and two oxygen atoms on the product side of the equation. 2 Adding a coefficient “2” in front of H 2 O corrects our oxygen problem, but now causes Hydrogen to be unbalanced... 2 Adding a coefficient “2” in front of H 2 corrects our unbalanced hydrogen problem. We now have the same number of hydrogen and oxygen atoms…It’s balanced!

Chemical Reactions Cu + AgNO 3 Cu(NO 3 ) 2 + Ag It is helpful to list the atoms involved and find out what is balanced and what is unbalanced (Hint = Polyatomic ions stay together!) Reactants Cu = 1 Ag = 1 NO 3 = 1. Products Cu = 1 Ag = 1 NO 3 = 2. Unbalanced

Chemical Reactions F 2 + H 2 O HF + O 2 Reactants F = 2 H = 2 O = 1. Products F = 1 H = 1 O = 2. Try this one on your own! Unbalanced Balanced!

Try this on your own and then learn a great trick NH 3 + O 2 N 2 O 4 + H 2 O Reactants N = 1 H = 3 O = 2. Products N = 2 H = 2 O = The only way to make 2 oxygen atoms into 7 oxygen atoms is to have a coefficient of 3.5. This is not acceptable. 3.5 Hint: Double all coefficients except the “problem” Now there are an even # of product oxygen atoms 7 14

Side #1Side #2 Checking both sides for a grade!