Oxidation-reduction Flashcards
Reduces other species by losing electrons
reducing agent
Oxidizes other species by gaining electrons
oxidizing agent
Common oxidizing agents are __, __, __ and _____, which favor gaining an electron to have a full octet
O2, O3, H2SO4, halogens
Common reducing agents are __, __, __ and ___ __ which favor losing an electron to have a full octet
H2, Fe, Zn, alkali metals
the total number of electrons that an atoms gains or loses electrons when a bond is formed
oxidation states
atoms in their ___ ___ have an oxidation number of zero. Oxidation numbers for atoms in ____ ___ are equal to their charge. __ is always assigned an oxidation number of -1, oxygen is often ___, and hydrogen is usually ___
elemental state, monoatomic ions, fluorine, +2, +1
__ ___ often have an oxidation number of +1, and ___ __ ____ often have an oxidation number of +2
alkali metals, alkaline earth metals
Exceptions are, if oxygen is in a ___, (___), it’s oxidation number is -1. If oxygen is bonded to fluorine the oxidation number of oxygen is ____. If hydrogen is part of a __ ___, the oxidation number is ____
peroxide, H2O2, +1, metal hydride, -1
To balance the redox reaction under acidic conditions, each ___ reaction must be written and firstly all atoms must be balanced other than __ and ___. Then balance the number of oxygen atoms by adding the same number of __ molecules to the opposite side. Balance the hydrogen atoms by adding __ to the opposite side. Balance the charges by adding ____. Multiply the equations to make sure each half reaction has the same number of ___, then add them together and cancel common terms
half, oxygen hydrogen, H2O, H+, electrons, electrons
In basic reactions the H+ must be balanced with ___ and then combined to create ____.
OH-, H2O
Electrochemical cells convert ___ energy to ___ energy or vice versa using __ __ and the movement of ___
chemical energy, electrical, redox reactions, electrons
Electrons always flow from the ___ to the ___
anode, cathode
energy produced from chemical reactions from energy stored in the bonds of atoms and molecules
chemical energy
energy produced from the flow of electrons
electrical energy
a cell that is spontaneous like a battery
galvanic (voltaic) cell
a non spontaneous cell like a rechargeable battery
electrolytic cell
In a galvanic cell, due to a chemical reaction in the battery ____, the __ builds up an excess of ___. Then electrons flow from the __ to the ___ spontaneously through the wire to produce ___. This process converts __ energy to ___ energy
electrolyte, anode, electrons, anode, cathode, electricity, chemical, electrical
Galvanic cells have a delta G ___ 0, the electrons move from the anode (__) to the cathode (__), they turn __ energy to ___ energy, do not require an external __ ___, have oxidation at the __ and reduction at the ___, and have a Ecell __ 0
< -, +, chemical, electrical, power source, anode, cathode, >
The salt bridge is a tube filled with __ ____. The anions from it flow towards the ____, which balances the increasing cations in the solution, and the ____ from the salt bridge flow to the ____ which balances the decreasing cations in the solution. As the reaction progresses the size of the ____ electrode increases, and the __ electrode decreases
nonreactive electrolytes, anode, cations, cathode, copper, zinc
Spontaneous redox reactions ___ electrons released by the anode, causing the battery to __ __ and not produce electricity
deplete, lose power
Electrolytic cells use a __ __ to force electrons to flow ___ in order to ensure the battery can be fully charged
power source, non spontaneously
In electrolytic cells, the delta g is __ 0, the electrons flow from the anode (__) to the cathode (__). ____ energy is converted to ____ energy, it requires an external __ __, oxidation is at the __, and reduction is at the ____, and the Ecell is __ 0
> , +, =, electrical, chemical, power source, anode, cathode, <
a porous barrier is a barrier that allows for the flow of __ and ___ charges like a salt bridge. The use of one is dependent on the design and not always ___
ions, neutralizes, necessary
When a power source forces the nonspontaneous movement of electrons to the cathode
molten electrolysis
In ____ one metal is plated with another to cover it in a thin layer. The metal being plated is made into the ___ and is the site of____
electroplating, cathode, reduction
The sum of the oxidation potential and reduction potential measured in voltage
Ecell
If Ecell __ 0, the cell is spontaneous. if Ecell is ___ 0 the cell is non spontaneous
> , <
Reduction potentials that are greater and more negative are stronger __ ___, weaker __ __, and want to __ electrons
reducing agents, oxidizing agents, lose
The moles of the product formed in electroplating is given by ____
I (current) (time)/number of moles of electrons transferred (F)
To find the change in free energy and cell potential, the following equation is used ___
delta G = -nFE
