1. Predict the products of a Double Replacement reaction.
2. Determine if a double replacement reaction will occur based on the products of the reaction and the Solubility Rules.
3. Balance a chemical equation.
This type of chemical reaction was also discussed on 01/18/2014 in a blog post titled “Double Replacement Reactions”.
In a Double Replacement Reaction (or double displacement), two compounds react to form two new compounds. The reaction of two aqueous solutions is typical at the introductory level.
For the reaction to occur, a product must leave the system and not stay as ions dissolved in solution. A solid, insoluble product known as a precipitate must be formed, or a pure liquid, or a gas which would leave the system.
A downward arrow is used to indicate a precipitate and an upward arrow is used to indicate gas formation.
The Solubility Rules aid in predicting the precipitate in a reaction.
Here is one chart:
Check in your chemistry department to see what is traditionally completed for this topic. Don’t reinvent the wheel!
Here’s a lab reacting six different solutions to provide 15 different reaction combinations to observe.
I have performed these type of reactions in spot plates, but also with a half sheet of plastic overhead place on top of the table. It can be easily slid away to write down notes or observe the solution on the black lab tabletop. Then the plastic sheet can be slid back into place.
Here is another lab – your students could provide their own data charts:
Here is a worksheet on Double Replacement reactions w/ answers:
You may have to aid your students with some chemical formulas.
I will try to have one more short post before Thanksgiving (11/27)!
Check out the Topic List to help you to find past Blog entries. I hope it helps!
The holidays approach, so buy my lab book "Chemistry on a Budget" (or ask for it as a gift) -- it is available for $20 at amazon.com or $23 at lulu.com. It will take a few weeks to get to you, so order now!
This book contains 13 labs using consumable materials purchased from local stores. There are two versions of each lab, one with a ten-question conclusion and one with directions for a full lab report. This way the teacher has the option! Each lab is two pages to allow for one two-sided handout.
Have a good week!