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DAVID LICATA's picture

Finding and Writing the Molar Mass of Elements [corrected]

Tue, 11/04/2014 - 20:09 -- DAVID LICATA
Finding and Writing Molar Mass Screenshot

This worksheet is intended to be used as a "Guided Instructional Activity" (GIA). It asks students to find the molar mass of selected elements and write the molar mass as two equivalent fractions ("conversion factors") and as an equality. In each representation, students are forced to give the numeral of the measure, unit, and identity of the chemical.

Time required: 

About 45 minutes.

DAVID LICATA's picture

Stoichiometry Fireworks Lab Quiz

Mon, 11/03/2014 - 21:39 -- DAVID LICATA
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.

DAVID LICATA's picture

Mass of a Reaction Product

Wed, 10/29/2014 - 21:41 -- DAVID LICATA
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.

Shelly Belleau's picture

Density "POGIL-Like" Activity

Mon, 07/14/2014 - 17:43 -- Shelly Belleau

Although many students have been exposed to the concept of density before reaching my Chemistry class, I always start the year with this POGIL-like activity.

Time required: 

Approximately one hour including the debrief (I recommend holding a whole-class discussion for the summarizing questions that follow the What is density? activity and a selection of mathematical computation problems from the How can you calculate density? activity.)


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