Element of the Day http://www.youtube.com/watch?v=uTm_wWAEz1Q
Re
Rhenium (ree­nee­әm) is a chemical element with the symbol Re and atomic number 75. It is a silvery­white, heavy metal. With an average concentration of 1 part per billion (ppb), rhenium is one of the rarest elements in the Earth's crust. The free element has the third­
highest melting point and highest boiling point of any element. Rhenium resembles manganese chemically and is obtained as a by­product of molybdenum and copper refinement. Rhenium shows in its compounds a wide variety of oxidation states ranging from −1 to +7.
Discovered in 1925, rhenium was the last stable element to be discovered. It was named after the river Rhine in Europe.
Nickel­based superalloys for use in jet engines contain up to 6% rhenium, making jet engine construction the largest use for the element, with chemical industry catalytic uses being next­most important. Because of the low availability relative to demand, rhenium is among the most expensive metals, with an average price of approximately US$4,575 per kilogram.
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What is the oxidation state of Re (aq)?
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Chemistry
1. Element of the Day ­ Re
2. Finish POGIL Activity
3. Laboratory Investigation
Announcements
Due Thursday: Finish Laboratory Investigation
Be sure to turn in Det. of an Activity Series Lab
Quiz on Redox Reactions Thursday
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POGIL Activity
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Electrochemical Cells
Learning Targets
• Experimentally explore electrochemical cells • Understand how redox reactions can generate electron flow (electricity)
• Be able to use an activity series to predict whether a single replacement reaction will occur or not.
• Be able to identify which reactants are being reduced, and which are being oxidized
• Be able to write balanced half reactions for redox reactions.
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Activity Series
Most Reactive
Mg
Zn
Pb
Cu
Ag
Reactivity = likely to be
oxidized. (give up electrons)
Least Reactive
Oxidized half reaction:
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Chemistry Lab Groups
Group 4
Group 1
Matthew R
Alderson
Daniel J
Connelly
Bill Lee Catherine E
Edwards
Dakota P
Rice Tiffany P
Lee Martin W
van Drunen
Group 5
Group 2
Dominique D'Onofrio Taylor Ahliquist
Anthony H
McMillan
Sara Turpen Timothy D
Taylor
Annika J
van Houte
Group 3
Indigo M
Larson Aidan K
Moore
Spencer T
Alpaugh
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Name:
Type Lab Report
Date: April 10, 2012
Title: Electrochemical cells
Partners: ________________
I. Question: Why do combinations of metals produce different voltages?
II. Procedure ­ include diagram
III. Data Table
Ag
Cu
Mg
Pb
Zn
Ag
Cu
Mg
Pb
Zn
IV. Observations
V. Analysis Questions: 1) Use info from your data table and your knowledge of reactivity to write half reactions for each pair of metals. Then write full reactions for each pair of metals and identify the cathode and the anode.
2) How is the difference in voltage similar to the relative positions of the metals in the activity series from the last lab? Explain your answer.
3) Briefly describe energy transfers and transformations during electrochemical reactions.
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Sodium–sulfur battery
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Exit Question
At the anode of a galvanic cell _____________ occurs as electrons are transferred.
Reminders
Due Thursday: Finish Electrochemical Cells Lab
Quiz on Redox Reactions Thursday
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