Students can identify and predict the products of different types of reactions.
Notes include types of reactions and the energy related to chemical reactions (chapter 17).
In a chemical reaction, things are being mixed together or broken apart in some way to create a whole new set of things. It is important to remember that in a chemical reaction matter is neither created OR destroyed. The atoms of matter in a chemical reaction are simply rearranged to form new substances.
Chemical equations are written to explain what is happening in a chemical reaction. For example, the equation below shows what happens when zinc metal is combined with hydrochloric acid.
Zn (s) + 2 HCl (aq) --> ZnCl2 (aq) + H2 (g)
Zn and HCl are called the reactants because they are what will be reacting in this reaction. Zinc chloride (ZnCl2) and hydrogen gas (H2) are the products because they are what is produced from this reaction. The arrow separating the reactants and products means "yeilds". In other words, the above reaction reads "zinc combines with hydrochloric acid to yield zinc chloride and hydrogen gas." Notice the parentheses next to each reactant and product. The letter or letters inside the parentheses indicate what state of matter the reactant of product is in. A list of symbols that you may find in chemical reactions is listed below with their meanings.
There are 5 types of chemical reactions: Synthesis, Decomposition, Single-Replacement, Double-Replacement,
Synthesis Reactions: A + B --> AB
Decomposition Reaction: AB --> A + B
Single Replacement Reaction: A + BC --> AC + B
Double Replacement Reaction: AB + CD --> AD + BC
Combustion Reaction: Hydrocarbon + O2 --> H2O + CO2
Use the following list of question to determine what type of chemical reaction you are witnessing. When you can answer "yes" to a question, then stop!
When balancing equations, your goal is to make the number of atoms of each element be equal on the reactant and product side. This can ONLY be achieved by changing the coefficient numbers in front of each substance. NEVER EVER CHANGE THE SUBSCRIPTS IN CHEMICAL FORMULAS TO BALANCE AN EQUATION!
The following is an interactive tutorial to assist in your understanding of balancing equations: Balancing Equations Tutorial
This is a summary that may help you as you try to predict the products formed from a chemical reaction.