What`s redox anyways?

advertisement
A tutor’s guide on teaching about
oxidation-reduction problems
By Stephanie Yan, Jennifer Zhang, and Farnaz Dayani
 Key concepts
 understand terminology
 Understand general trends in oxidation states of various elements
 understand concept of valence electrons and that valence electrons does NOT
always correspond with oxidation number
 Student's difficulty
 Student is able to understand redox reactions with oxygen and hydrogen, but
has difficulty with ones that don't only involve O2- and H+
 Student sometimes gets confused with words like "oxidation reaction, oxidized
element, and oxidizing agent”
 student has not yet learned to balance redox equations
 First, make sure the student understands that:
 oxidation means gain of oxygen or loss of electrons
 reduction invovles loss of oxygen or gain of electrons
 Show a problem that includes gain or loss of oxygen
 Show solution
reduction: CuO gets reduced
CuO+ H2 Cu + H2O(loss of “o”)
gaining oxygen, SO3(2-) gets oxidized ,SO3(2-) + H2O= SO4(2)(gain of “o”)
 Show a problem that does not involves loss or gain of
oxygen
 Show solution
EX: Zn + CuSO4= ZnSO4 + Cu
Zn(0) – 2e- -------Zn2+ lose electron, gets oxidized
CU2+ 2e- --------CU(0) gain electron, gets reduced, occurs reduction
 In solution, include that the element that is reduced is the oxidizing agent
and the element that is oxidized is the reducing agent
 explain oxidation state and numbers (O is always 2-, H is usually +1, figure
rest out from total compound/molecule's charge
 Explain how to solve for an element’s oxidation states in absence of O2and H+
 use boxes with arrows and letters up/down O(r)R(a),
down/up R(r)O(a)
↑
↓
O
R
↓
↑
R
O
O.S
Electron
Reaction
Agent
 Love story between Mr. Orra and Ms. Rroa and flowers are
e you cannot marry yourself/ be a husband-wife so you can't be
the oxidizing agent AND be oxidized. Therefore if you are
oxidized, you are the reducing agent.
 LEO the lion says GER (can also be visual verbal)
 Lose Electron = Oxidation
 Gain Electron = Reduction
 When you gain an electron, the charge is actually reduced
because electrons are negative charge
 Story telling along with previous example of love story
(once upon a time, there was a guy named ORRA…………)
Download