The “Elephant Toothpaste” experiment is a very popular, albeit messy chemistry demonstration. To carry out this experiment, place a 250 mL graduated cylinder on something that you wouldn’t mind getting messy.
HS-PS1-2 Chemical Reactions
This is a Chemical Reactions lab that I modified to meet NGSS guidelines.
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.
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.
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.
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.
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.
Students will proceed through a pre-lab engagement activity, organize element cards based on similarities & trends, discuss trends with the class and then produce a periodic table that includes the trends discussed within the lab.
Students choose a topic and select items to incorporate into a periodic table. Students explore trends related to their own topic and relate to the trends on the actual Periodic Table of Elements.