Most school budgets are depleted for the 2015-2016 class year. The book Chemistry on a Budget contains inexpensive chemistry labs that could be useful. You can buy this lab book for $23 at amazon.com or lulu.com. Check it out!
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.
It will take a week or so to get to you, so Order Now!
*Some of you have purchased my lab book – be sure to check out Page 141 !
Past blog posts that may be useful at the end of the school year include:
-Final Exams – End of Year Preparation dated 06/08/2014
- End of Year Activity – Lab Clean-up dated 06/15/2014
- Lab Practical Examination dated 04/30/2015
- Final Exams II dated 06/04/2015
You may be talking about Acids, Bases & Salts at this time of year or could review the concept in a few weeks.
Salts are ionic compounds derived from Acids and Bases. The ions produced when a salt dissolves react with the hydrogen and hydroxide ions in water produce small amounts of the original acid and base. A hydrolysis reaction of a salt can produce a slightly acidic or basic solution.
Because this basic concept of salt hydrolysis is not that difficult to master, it tends to be discussed briefly in Introductory Chemistry. It is covered more in depth (discussing the equilibrium system of the acid/base/salt/water solution) in an Advanced Placement (AP) Chemistry course. There may be a laboratory that is already being performed in your department based on this topic.
Here is a video of a classroom demonstration of salts and the pH of the solutions they produce:
Here is a PDF file from Flinn Scientific to provide instructions on how to perform this demonstration:
It would be a lot of work to gather the chemicals necessary for this demonstration – see if any teachers in your department are already performing it.
A very simple desktop demonstration would be to have students predict the pH of a baking soda solution. Then, wearing goggles, they could dissolve the baking soda in water in a spot plate (or small beaker) and test it with pH paper.
Discovering that it produces a basic solution, the question is “Why does baking soda produce a basic solution?”
From there you can show the hydrolysis reaction for sodium hydrogen carbonate (NaHCO3).
The reaction for the hydrolysis of sodium hydrogen carbonate can be written as follows. H(OH) is being used (instead of H2O) to show the movement of the H+ and OH- ions:
NaHCO3 + H(OH) -> NaOH + H2CO3
Sodium hydroxide (NaOH) is a strong base and hydrogen carbonate (H2CO3) is a weak acid, and the resulting solution is slightly basic.
An interesting extension of this discovery, that baking soda produces a basic solution, is to share (or have your students research) the household uses for baking soda.
For example, these various websites list uses for baking soda including making toothpaste, use as an antacid, and various cleaning applications. Because baking soda (sodium hydrogen carbonate) produces a slightly basic solution, it is a very effective cleaner. I used it recently, slightly dampened (sort of a slurry) to easily clean out tea stains from porcelain coffee mugs.
*This Blog contains several entries that would be helpful to your chemistry classroom. Check out the Topic List to help you to find past Blog entries.
Also, Write To Me about your successes, challenges, or questions in the Chemistry Classroom.
Remember, buying a copy of the lab book Chemistry on a Budget can be very useful to your Chemistry classroom with labs and class article ideas.
Have a great week!