HS-PS1-2 Chemical Reactions

Rethinking Stoichiometry

Stoichiometry is arguably one of the most difficult concepts for students to grasp in a general chemistry class. Stoichiometry requires students to synthesize their knowledge of moles, balanced equations and proportional reasoning to describe a process that is too small to see. Many times teachers default to an algorithmic approach to solving stoichiometry problems, which may prevent students from gaining a full conceptual understanding of the reaction they are describing. 

Relative Reactivities of Metals

Last winter I watched a webinar put on by ACS and AACT called "NGSS in the Chemistry Classroom." As a result of watching that webinar, I took an activity that had NGSS Science & Engineering Practices (SEP) integrated into it and tried it out in class. In this activity, students are required to develop their own procedures and data tables.

Mass of a Reaction Product

Students combine sodium carbonate and hydrochloric acid generating carbon dioxide gas which is allowed to escape. They measure the actual yield of carbon dioxide produced (missing mass), calculate the theoretical yield using stoichiometry, and then the percent yield. Students understand that 100% yield is the most appropriate answer (based on the Law of Conservation of Mass), so after considering the meaning of significant figures and the uncertainty of their measurements they are asked to decide if they did (or did not) get an answer that might indicate the validity of the Law.

Complex Ions Lab

This laboratory exercise accompanies the article "A guided group inquiry lesson on coordination compounds and complex ions". The laboratory serves as part of an extended exercise on the chemistry topic of coordination compounds and complex ions. The entire lesson as described in the article also exposes students to how chemical research is conducted and the conflicts and uncertainties that lead to new theories and discoveries.

Types of Chemical Reactions

I expect that most high school chemistry teachers assign some type of laboratory related to types of chemical reactions including synthesis, decomposition, single replacement and double replacement reactions. I have used several published versions, but I am sharing my modifications. 

Energizer Lab - A Target Inquiry Activity

This lab was written as part of the Target Inquiry program at Grand Valley State University in Michigan. Students build an electrochemical cell, learn about the symbolic equations used in electrochemistry and manipulate a model representing the particulate level of what is happening during the electrochemical process.