Reagents, Compositions, Weight Loss
This is a short experimental study of several different reagents and what happens to them when they are heated to 110° and 1200° C.
Skills and concepts that students must have mastered
Students should have knowledge of basic chemistry and of minerals equivalent to what they would learn in an introductory geology class.
How the activity is situated in the course
This activity is the 1st of 36 mineralogy exercises and is used at the beginning of the course.
Content/concepts goals for this activity
- Review Periodic Table of Elements.
- Understand that similar reagents may have dissimilar compositions depending on where they were made.
- Reinforce and expand knowledge of and gain confidence working with formulas, atomic weights, moles and grams, and converting weights.
- Prepare students for future making of synthetic minerals.
Higher order thinking skills goals for this activity
- Understand and apply basic chemical principles.
- Complete experiments and analyze and interpret results.
- Reconcile varied results among different groups.
Other skills goals for this activity
- Develop group work skills.
- Learn importance of good, careful lab techniques.
- Be able to take good notes.
- Enhance report writing skills.
- Enhance public speaking skills while defending results.
Description of the activity/assignment
This is a short experimental study of what happens to aluminum hydroxide, silicic acid, magnesium oxide, and calcium carbonate (or reagents of instructors choice) when they are heated to 110 and 1200 degrees.
- Students determine the formula and calculate the mole percent and weight percent of each element and oxide in each reagent.
- They heat the samples and calculate percentage weight loss or gain.
- Finally, they write a lab report summarizing their results.
Be sure to have students save their samples for later use in a lab that introduces X-ray diffraction.
Determining whether students have met the goals
Student peer comparison of results reveals who has recieved the most reasonable results. Student reports may be evaluated for inclusion of measurements, description of experiment process, prediction of what might happen, description of what really happened, and comparison of other groups results.