Michael Jansen reflects on a very common empirical formula lab that asks students to determine the empirical formula of MgxOy. He then explains how he continues to use it as a "successful failure", how he demonstrates an alternate procedure and leads his students to an important lesson.
Writing formulas is one of those concepts in chemistry that requires much practice and repetition for students to gain confidence. This remote learning activity is a fun way for students to practice name and formula writing that will not be as boring as a worksheet full of practice questions.
Determining the empirical formulas of ionic compounds based on charge balance is often a challenge for beginning chemistry students. Many visual aides have been developed for this purpose, from repurposing commercial interlocking bricks to custom 3-D printed bricks. This article describes yet another option– upcycled can carriers.
Nomenclature is a tough topic. I tell students that we are living in the land of symbols while we study nomenclature. It is important but it is difficult to get them excited. I started fishing for resources. The American Association for Chemistry Teachers (AACT) has been a great resource to help me try new things.
According to the app store description, Chemical Formula Challenge is "An educational game to improve your ability to form chemical formulas from chemical names. You can either play it yourself or challenge a friend". The app features different levels of play such as easy, normal, and hard regarding the difficulty of the ions. As an example, beryllium chloride is considered "easy" while lead II nitride is considered "hard". The app then gives the user several ions to choose from and the user must then select the correct number of ions needed to balance the formula correctly.
There is a hydrate lab which is done by many teachers. Typically, students first use a known hydrate and are provided the formula. As an example, they might use CuSO4 . 5H2O. On paper, they would work through the percent by mass of water in copper (II) sulfate pentahydrate. They then would be given a mass of the copper (II) sulfate pentahydrate, calculate how much water they should lose and then they would heat it and compare the data with the calculated value. Next, they are given an unknown hydrate. They are also given the molar mass of the unknown salt of the hydrate and they have to calculate the molar ratio of salt to water based on their data. Here is one possible way to “tweak” this lab.
This activity is used as a reinforcement activity following my use of JCE Classroom Activity #113: An Interlocking Building Block Activity in Writing Formulas of Ionic Compounds. It could be used as a stand alone activity to support writing ionic formulas and names.