Biology

Levels of Organization in Ecology
PBS DNA Workshop (HS-LS1-1)
What are Enzymes? (HS-PS1-5, HS-LS1-1)

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Oxidation of Magnesium - Empirical Formula

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This video summarizes an experiment performed to experimentally determine the empirical formula of magnesium oxide. In the lab the mass of a small sample of magnesium ribbon is measured. The metal is then heated in a crucible using a Bunsen burner to speed up the process of oxidation. The reaction forms the product magnesium oxide. The mass of this compound is measured and compared to the original amount of magnesium to determine the added mass of oxygen. The data collected allows students to calculate the empirical formula of the magnesium oxide compound. The reaction is summarized by the following chemical equation. 2Mg  +  O 2  →  2MgO The compound forms with a 1:1 ratio of magnesium to oxygen. This is because magnesium has two valence electrons which are donated to the oxygen atoms. The oxygen atoms can add two electrons to complete their valence shell. I hope this was helpful.
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HS-PS1-2: Trends of the Periodic Table

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HS-PS1-2:   Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties. This video covers important trends of the periodic table.  Topics include; reactivity, ionization energy, successive ionization energy, atomic radius, ionic radius, electron affinity, and electronegativity.
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Radioactive Dinner Plate

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This video shows two plates being measured for emission of radiation. The orange Fiesta plate was made using a glaze which contains uranium oxide. Fiesta dinnerware was produced by the Homer Laughlin China Company of West Virginia. Prior to World War II the glazes used natural uranium.  This practice stopped during the war when the US government seized the company's stock of uranium for the Manhattan Project.  In the late 1950's the Atomic Energy Commission relaxed restrictions on uranium and production practices switched to using depleted uranium to produce the red-orange glaze. The US Environmental Protection Agency recommends that dinnerware produced with uranium glaze should not be used for food, drink or food storage.
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