Do Now: • List the 5 types of chemical reactions • Write a BCE (balanced chemical equation) for the following reactions: • Copper wire is dipped into a solution of silver nitrate. • Sufuricacid (H2SO4) is poured over a small chunk of zinc. • A gold ring is dropped into a beaker of hydrochloric acid (HCl).
Topic H - Reactions “Double Replacement Reactions”
Objective At the end of this lesson students should be able to: • Correctly identify a double replacement as such. • List the 3 ways to tell when a double replacement will occur. • Correctly balance a double replacement reaction. Purpose This is the 3rd section on balancing chemical equations. After this lecture you should be able to organize, analyze, and balance any equation.
Review types of chemical reactions There are multiple schemes for classifying chemical reactions. In this class we will use the following divisions: 1) Synthesis A + B AB 2) Decomposition AB A + B 3) Combustion CxHY + O2 CO2 + H2O 4) Single Replacement AB + C CB + A 5) Double Replacement AB + CD CB + AD
Review signs of a chemical reaction A chemical reaction may have occurred if any of the following indications are present. 1) Release of light/heat 2) Bubbles 3) Color change 4) Formation of a precipitate
Double Replacement AB + CD CB + AD Double replacement reactions occur when one of three conditions are met: 1) Formation of a gas (bubbles) 2) Formation of a molecular compound (like water) 3) Formation of an insoluble compound (precipitate) In other words, at least one of the products must be bonded very tightly together.
Remember the School Dance? Consider high school students that go to a dance. Here is their order of popularity: Girls Boys Abby Apple Daniel Drum Betty Banana Floyd Flute Carol Citrus Ted Trumpet
School Dance Suppose that Abby Apple and Ted Trumpet go to the dance together and happen to see Floyd flute there with Betty Banana. What will happen?
School Dance Suppose that Abby Apple and Ted Trumpet go to the dance together and happen to see Daniel Drum there with Betty Banana. What will happen?
Solubility Diagram Soluble? • Ag2SO3 • LiNO3 • K2CrO4 • Zn(CN)2 • Na2CO3 • AuS • CaF2 • PbCl2 • Ba3(PO4)2 • Ba(OH)2
Using your solubility chart Just like the table in the school dance example, there is a solubility table for chemicals! Example: Suppose a solution of barium chloride is mixed with a solution of sodium sulfate. Will a reaction occur? Write a BCE. (balanced chemical equation)
Practice • Silver nitrate is mixed with sodium chloride. Write a BCE. 2. Calcium iodide is mixed with lithium phosphate.
Review At the end of this lesson students should be able to: • Correctly identify a double replacement as such. • List the 3 ways to tell when a double replacement will occur. • Correctly balance a double replacement reaction.