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Activity Series & Redox. Metal Reactivity Lab Results. 1. What metal is the most reactive? How do you know?. 2. What metal is the least reactive? How do you know?. 3. Which metal would most likely be found in elemental form in nature? (not in a compound, but just as an element).
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Metal Reactivity Lab Results 1.What metal is the most reactive? How do you know? 2. What metal is the least reactive? How do you know? 3. Which metal would most likely be found in elemental form in nature? (not in a compound, but just as an element) 4. Design an activity series with these 4 metals. Put the most reactive metal at the top and the least reactive on the bottom
Li+!! Activity Series p. 121 Which is the most active – Li+ or Au+?
Yes it reacts Will a reaction occur between Li & AuCl? • For a reaction to occur the pure metal must be higher on the series (more reactive) than the metal in the compound Au What is the metal in AuCl? Is Li+ more reactive than Au+? Li + AuCl LiCl + Au
Which of the following reactions will occur? • Al + AgNO3 --> • NaCl + Ca--> • KBr + Zn --> • Li + AgNO3 --> Is the free element above the element in the compound? Al(NO3)3 + Ag Yes CaCl2 + Na Yes No – no reaction LiNO3 + Ag Yes p. 121
CuS2 Reduction– making something smaller – from ore to pure element. • gain of e- gives ion a reduced charge • EX: Chlorine (Cl) = 17p+ & 17e- • Gains 1 e-… What happens to the chg #? Bigger or smaller? • Chloride (Cl-)= 17p+ & 18e- = -1 charge Example: Formation of pure Cu Metal Cu 2+ + 2 e- Cu copper II electrons copper ion (ore) metal Where would you find a Cu2+?
Oxidation • Loss of e- results in ion left with more protons (+ charge) • Ex: Copper = 29p+ & 29e- • Copper II = 29p+ & 27e- = +2 charge Formation of Copper II ions Cu Cu 2+ + 2 e- copper copper II electrons metal ion Which copper is in a compound? Which is the pure copper? If metal chemically combines with oxygen, can it remain neutral?
Oxidation / Reduction • Redox – electrons lost by one element are gained by another • ALWAYS happen together! • OIL RIG • Oxidation is Losing • Reduction is Gaining
+ 2+ Identify what is being oxidized and reduced. 3+ 1- 0 1+ 1- 0 • Al + AgNO3 --> Al(NO3)3 + Ag • Na + Ca--> Ca + Na Al Oxidized is loss of electrons = becomes more positive Reduction is gain of electrons = # is reduced Ag When do elements have a charge? Elements have a charge when in a compound. Ca Oxidized = Reduced = Na+
NO tutorials this Friday! Tutorials will be Thursday 8:15am in D204 4:15pm in D219 • Monday, October 24, 2005 • WU: see OH • Check: Check: p109 #1,2,6,8,9,12-17 • p.126 # 1,2,7,13-16 • Notes on Redox in Mining & Refining • Redox! Where are the electrons? WS • (same as MM pp124-125) • HW: 1. p127 #9-12 • 2. Study for Quiz on Wed over • Unit 2 Sec AB
Redox in Mining & Refining • Used to reduce metal cations in a compound to purify metal • Cu2S + Na Cu + Na2S • Cu + + e- Cu
Review ore to a penny? p. 115
How geologists evaluate an ore: (p. 113) • Percent of metal in ore ! • Quantity of available ore • Type of mining & processing • Distance of mine to refining facility & markets • Supply and demand status
Techniques used to reduce/purify metals • Electrometallurgy –use electric current to supply e- • Pyrometallurgy – heat causes rxn w/ CO2 which supplies e- • Hydrometallurgy – reactants in water solution supply e-
Resources are limited • Conservation-preserve, don’t use • Reuse-use again in same form • Recycle-break down, reform & use for something else
Pt+2+ Cu Pt+ Cu+2 REDOX WS #1 Is pure element above element in cmpd? • Will rxn occur? • Draw e-dot c. Reactant oxidized? Reactant Reduced? d. Oxidizing reagent? Reducing Agent? Yes Pt+2 CuCharge decreased Agents are opposite. They caused it to happen. Pt+2 Cu