Chem #11 Flashcards
LEO GER
loses electrons oxidized (+)
gains electrons reduced (-)
oxidation-reduction reactions
always occur in pairs and focus on the movement of electrons.
o Involve the transfer of electrons from one chemical species to another.
law of conservation of charge
electrical charge can neither be created nor destroyed.
oxidation
loss of electrons
oxidizing agent
causes another atom in a redox reaction to be oxidized and is itself reduced.
Common oxidizing agents contain oxygen or similar electronegative element
reducing agent
causes another atom in a redox reaction to be reduced and is itself oxidized.
Common reducing agents contain metal ions or hydrides (H-)
reduction
gain of electron
specificity about oxidizing agent and reducing agent terminology
These are applied specifically to the atom that loses or gains electrons.
changes in oxidation state in transition metal results in ____
change in color
how do formal charge and oxidation state differ?
Differ from formal charges in that formal charges assume equal sharing of electrons in a bond whereas oxidation numbers assume unequal sharing with more electrons going to the more EN atom.
oxidation numbers
assigned to atoms in order to keep track of the redistribution of electrons during chemical reactions.
Can look at how many electrons are gained or lost by each atom this way.
what is the oxidation # of free element
0
if it gets oxidized, it is the ____ agent
reducing agent
how to balance a redox reaction
o Both the net charge and the number of atoms must be equal on both sides of the equation.
o Use the half-reaction method: balance the oxidation and reduction reactions separately and then add them together.
complete ionic equations
if we split the various species into all of the ions present.
spectator ions
inert ions that are present during the reaction but are not taking part in it.
net ionic equation
take out spectator ions, aqueous compounds should be split into their constituent ions, but solid salts should be kept as a single entity.
disproportionation (dismutation)
a specific type of redox reaction in which an element undergoes both oxidation and reduction in producing its products.
o Biological enzymes that do these reactions and redox reactions often have metals in their active sites that act as reducing agents.
oxidation-reduction titrations
o Follow the movement of electrons to reach the equivalence point.
o Use indicators that change color at a particular voltage (emf) value.
o Potentiometric titration: a form of redox titration where no indicator is used. Electrical potential voltage is measured instead.
dehydrogenases perform ____
oxidation
oxidizing agents oftentimes contain ______
oxygen or strong electronegative element
what are the oxidation states of the elements in HOCl
H: +1, O: -2, Cl: +1
O is more EN than Cl
what are the oxidation states of the elements in NaH
Na: +1
H: -1
what are the oxidation states of the elements in O2^-2
-1
