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IDENTIFYING TYPES OF CHEMICAL REACTIONS1)  Does your reaction have oxygen as

one of its reactants and do its products all contain oxygen? If yes, then it's a combustion reaction.

2)  Does your reaction have two (or more) chemicals combining to form one chemical? If yes, then it's a synthesis reaction.

3)  Does your reaction have one large molecule falling apart to make several small ones? If yes, then it's a decomposition reaction.

IDENTIFYING TYPES OF CHEMICAL REACTIONS 4)  Does your reaction have an uncombined

element on the left side and on the right side? If yes, then it's a single displacement reaction.

 5)  Does your reaction have water as one of the products and an acid as a reactant? If yes, then it's an acid-base reaction

 6)  Does your reaction have two ionic compounds that "switch partners"? Then you've got a double displacement reaction

IDENTIFY REACTION TYPES

1)  KOH + NaNO3--> KNO3+ NaOH  2) Sn + Cl2--> SnCl2

 3)  CaCO3--> Ca + CO2

 4)  CaSO4+ Mg(OH)2--> Ca(OH)2+

MgSO4

 5)  KOH + HCl --> H2O + KCl  6)  C4H8+ O2--> CO2+ 2 H2O

7) Ag + ZnCl2 --> AgCl+ Zn

BALANCING CHEMICAL EQUATIONS

Why do we need to balance equations, anyway?

"In a chemical reaction, matter is neither created nor destroyed."

 

When we write chemical equations, we start with the formulas for the reactants on the left side (what you start with) and the formulas for the products (what you end with) on the right. If we were to simply put the formulas of the chemicals on the left and right without saying how much of each was going to react, then we could not guarantee that the mass of what we end with is the same as the mass of what we started with, and we would be in violation of the law of conservation of mass (call the matter police!)

BALANCING CHEMICAL EQUATIONS

1. Start with an unbalanced equation. I might give this to you, or I might make you figure it out. Either way, if you don't have an equation with all the chemical formulas and the arrow, then you're out of luck.

 

2. Draw boxes around all the chemical formulas. Never, ever, change anything inside the boxes. Ever. Really. If you do, you're guaranteed to get the answer wrong.

 

BALANCING CHEMICAL EQUATIONS CONTINUES3. Make an element inventory. How are you

going to know if the equation is balanced if you don't actually make a list of how many of each atom you have? You won't. You have to make an inventory of how many atoms of each element you have, and then you have to keep it current throughout the whole problem.

 4. Write numbers in front of each of the boxes

until the inventory for each element is the same both before and after the reaction. Whenever you change a number, make sure to update the inventory - otherwise, you run the risk of balancing it incorrectly. When all the numbers in the inventory balance, then the equation is balanced.

 

TIPS FOR BALANCING:

1.Start with elements that are only in one reactant and in only one product.

2.Save oxygen and hydrogen for last.

3.If you are working with a single or double displacement reaction, treat polyatomic ions as a unit.

4.Use a least common multiple to balance when needed.

5.If all elements will balance except one, double the largest molecule (the one with the most molecules) and then rebalance.