wisigehe's version from 2016-05-19 21:16



Question Answer
in a redox reaction, ___ are transferred from one atom to anotherelectrons
atom that loses electrons isoxidized
atom that gains electrons isreduced
mnemonic for identifying oxidized/reduced atomsLoseElectronOxidized says GainElectronReduced
reducing agentcompound containing atom that gives electrons up
oxidizing agentcompound containing atom that accepts electrons
CH4 + 2O2 --> CO2 + 2H2O; reducing/oxidizing agent?CH4 is reducing agent; dioxygen is oxidizing agent

Oxidation states


Question Answer
atoms in their elemental form0
hydrogen NOT bonded to metal+1
oxygen NOT in peroxide-2
hydrogen bonded to metal-1
group 1 elements (alkali)+1
group 2 elements (alkaline earth)+2
N family-3
O family-2


Question Answer
oxidation statepossible charge values that an atom may hold within a molecule; usually don't exist, just useful for keeping track of electrons in redox reaction
sum of oxidation states of atoms in a neutral molecules must equalzero
sum of oxidation states of atoms in a charged molecule must equalcharge of molecule
general guideline for oxidation stateatom's variance from noble gas configuration
which atom gets state priority? N vs. Ooxygen
oxidation state of O in NO3--2 (O gets priority); N is +5; 5 - 6 = -1
2H2 + O2 --> 2H2O; _H__ is oxidized and __O_ is reducedH; O

Redox titrations


Question Answer
fx of redox titrationfind [reducing agent] by titrating with strong oxidizing agent of known molarity
Sn2+ + Ce4+ --> Sn4+ + Ce3+ (unbalanced); # moles of Ce4+ required to reach equivalence pt?twice the number of moles of Sn2+ in solution (one e- required to reduce Ce4+ but two e-s required to oxidize Sn2+)
how to identify equivalence pt?voltage compared to standard solution instead of pH

Balancing redox equation


Question Answer
steps to balance redox rxn occurring in an acidic soln1 divide reaction into half reactions; 2 balance elements other than H and O; 3 add H2O to one side until O atoms are balanced; 4 add H+ to one side until the H+ atoms are balanced; 6 add e- to one side until the charge is balanced; 6 multiply each half reaction by an integer so that an equal number of electrons are transferred in each reaction; 7 add the two half reactions; simplify
steps to balance redox rxn occurring in a basic solnsame as acidic soln; neutralize H+ ions by adding the same number of OH- ions to both sizes of the reaction