Solution to Chemical Mystery #8, and...a challenge!
aqueous solution chemistry
Analytical Thinking, Analytical Action
The November 2016 issue of the Journal of Chemical Education is now available online to subscribers. Topics featured in this issue include: electrochemistry; researching how assessment aids learning; using technology to teach; environmental chemistry; hands-on, minds-on activities and demonstrations; geology-inspired chemistry.
Addition of a white solid to a green solution causes the solution to separate into some truly beautiful colors...
Solution to Chemical Mystery #6 is presented. Also, concepts related to the chemical can crush demo are briefly discussed.
Just the other day within my IB Chemistry HL classes, we were discussing the color of transition metal complex ions in solution. It's a bit imperfect, because they are not yet dissolved, but I set up a number of metal chloride salts in order to help students see the pattern. They are arranged according to the position of the metal in the periodic table. It ends up being quite obvious to the students that the only metal salts with color are in the d-block. I'm now in the process of ordering more chloride salts so I can complete the pattern even more the next time I teach this topic.
In this Activity, students investigate a classic chemistry demonstration that uses the phenomenon of freezing-point depression to lift an ice cube out of a glass of water with a thread. They first test how adding salt, pepper, cream, and sugar to cold water affects the temperature.
In this Activity, students investigate the chemistry of the popular Salt Crystal Garden. They grow salt crystals by evaporation from aqueous solutions containing various mixtures of table salt, ammonia, and laundry bluing in order to determine the purpose of each component.