Stoichiometry Fireworks Lab Quiz

Ignition of sugar and potassium chlorate produces purple flames and sparks.

Given the amount of one reactant, students must use stoichiometry to find the ideal amount of the second reagent to use to create purple fireworks. The teacher ignites each groups' fireworks. Ideal mixture create little or no ash. Student assignment sheet with directions (and different initial amounts) plus teacher information and sample answers are included. This is an exciting and engaging activity that can be used as a stoichiometry quiz.

Time required: 

With one balance per table (two groups), the calculations should take about 10 minutes, the measures another 10 minutes. Ideally, students should be prepared to deliver their mixture to the teacher within 20 minutes. In practice, many students will take longer, particularly if the formula for potassium chlorate is not given and students are not familiar enough with ionic nomenclature.

The teacher will need about one minute per group to announce the group's mixture, ignite it, and wait for student responses. So if there are 15 groups, the teacher should allow about 15 minutes to ignite all the mixtures.

Mass of a Reaction Product

Sodium carbonate reacts with hydrochloric acid producing bubbles

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.

Time required: 

One 50-minute period to perform the lab. One additional period to perform the calculations (optional). Often more able students will have time to begin some calculations at the end of the lab experiment.

JCE 91.10—October 2014 Issue Highlights

Journal of Chemical Education October 2014 Cover

Communicating the Value of Chemistry
The October 2014 issue of the Journal of Chemical Education is available online to subscribers []. The October issue features sustainability; celebrating National Chemistry Week 2014 with articles on food and candy; increasing chemistry understanding for the nonscientist; nanochemistry; investigating materials: plastic & paper; exploring sound; research on chemical equilibrium instruction and student understanding of scale.

JCE 91.09—September 2014 Issue Highlights

Journal of Chemical Education September 2014 Cover

Advanced Placement Chemistry Special Issue
The September 2014 issue of the Journal of Chemical Education is available online to subscribers []. The September issue features a special issue of 20 contributions on Advanced Placement (AP) Chemistry as well as many other articles to help students learn chemistry.

Photoelectron Spectroscopy Special Issue Article

The new AP Chemistry curriculum is in the second year of use. Photoelectron spectroscopy (PES) is a topic that generated much discussion because it is an addition to the curriculum. Jamie Benigna of Michigan teaches AP Chemistry, is an AP reader and recently wrote an article about PES for the Journal of Chemistry Education Special Issue. The article discusses the rationale for including PES in the course, explains some background of PES and provides strategies for including PES in your own course. This article is offered as a free preview of the AP Special Issue. 

Scientific Practices Post #2: Conclusions from Evidence

In this post I would like us to consider the ways teachers can help support and scaffold the process of making claims and drawing conclusions on the basis of evidence.  Not only is this grounded in the scientific practices addressed in the Next Generation Science Standards (a centralized them

Simple Activities to Integrate Particle-Level Diagrams

There have been many conversations within the Chemistry Education community surrounding the revisions to the AP curriculum. Twitter has been buzzing with instructors debating how to implement the changes, conferences and workshops have participants deconstructing the data from last year’s exam, and classroom teachers are working diligently to prepare their students for this year’s test.

One way the College Board has tried to shift the AP curriculum away from algorithmic problem solving and toward more meaningful conceptual understanding is through the use of particle diagrams.