Unit 2: Electrochemistry Flashcards
What is oxidization
Loss of e-
What is electrochemistry
The branch of chem that studies e- transfer on chemical reactions
What is reduction
Gain of e-
What are half reactions
Oxidization and reduction occurs together, and are half reactions when looked at separately
What does “adding” the half reactions together do
Gives you the net ionic equation
What rule do half equations have to follow
e- lost must = e- gained
Spectator ions are not included
What is an oxidizing agent
What is a reducing agent
Oxidizing agent: A reduced subject (gained e- and oxidizes other subjects)
Reducing agent: An oxidized subject (lost e- and reduces other subjects
What constitutes as a spontaneous reaction?
When they occur on their own without input of additional energy
What is the redox spontaneity rule
Spontaneous reactions occur if the OA is higher than the RA on the half reactions table
List the steps to predict redox reactions
1) list all reactants, dissociating soluble compounds and acids, always include H2O(l) & include h+ ions if an acid
2) identify as OA or RA & find the SOA and SRA
3) write out hr for SOA & SRA, find bet ionic reaction
4) determine spontaneity
How do you make a redox table?
You’ll be given data for certain ions and elements (possibly fictional ones) & write a table as reduction hr (+e-)
What is an oxidization number?
What is it used for?
The charge an atom appears to have when found in a neutral molecule/changed polyatomic ion
Used to determine if oxidization or reduction is happening if you have a molecular compound with no ion charge
How do your classify a change oxidization number?
1) if # ^, (becomes more +), then oxidization had happened
2) if # decreases ( becomes more -) then reduction has happened
What are the rules for assigning oxidization #’s
1) in a pure element, ox# = 0 (ions aren’t pure elements!)
2) in simple ions, ox# = the charge
3) in most compounds with hydrogen, for H, the ox# = +1 (except in metal hydrides, where ox# = -1)
4) in most compounds with oxygen, for O, the ox# = -2 (except peroxides)
5) the sum of ox# of all. Atoms in substance must = bet charge of the substances (0 for compounds, the charge for polyatomic ions
