# Empirical Formula PRE LAB

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Empirical Formula PRE LAB
Sean Dowling
Julia Phaltankar
Mrs. Oakes
Chemistry w/ Algebra 10/G
February 18, 2015
Determining Empirical Formula Lab
Introduction:
One can find an empirical formula by taking a sample of a compound and dividing the number of moles of one element in the compound by the number of moles of another element in the compound to form a small whole­number formula. For example, in a sample of a made up compound of oxygen and lead, one mole of lead has a molar mass of 207.2 g/mole, and oxygen has a molar mass of 16 g/mole. If this compound forms in a one to one atom ratio, then the ratio of moles will be 13 moles of oxygen to 1 mole of lead. In the experiment, the students will find the empirical formula of a compound containing magnesium and oxygen. Based on prior knowledge, the student believes that the ratio of magnesium cations to oxygen anions will be one to one. The student also believes that the ratio of moles of magnesium to moles of oxygen will not be one to one. Materials and Equipment:
Equipment:

Crucible
Crucible Tongs
Clay Triangle
Ring Stand w/ Clamps
Bunsen Burner
Electronic Balance
Wire Gauze
Electronic Balance
Scissors

Materials: ● Soapy Water

● Magnesium Ribbon Safety: Be cautious with hot crucibles and crucible covers as they can cause burns when in contact with skin. To avoid coming in contact with hot materials, tie back long hair and secure loose clothing.
Wear an apron, goggles, and closed toed shoes while performing the lab to protect from falling chemicals, glass, etc. Finally, while performing the lab, keep Magnesium away from open flames at all times. Procedure:
1. Refer to handout

Results: Data Table

Mass (g)

Crucible

Crucible+magnesium

Crucible +
Magnesium oxide

23.4433

23.7018

23.8894

Observations:
1. Clay triangle and crucible glow red when heated by bunsen burner.
2. While being strongly heated, Mg appears