Unit 13 - Electrochemistry
... the relationship between electric forces and chemical reactions.
Voltage: The potential difference or electromotive force,
measured in volts; it represents the amount of work that moving
an electric charge between two points would take.
Electrode: A conductor used to establish electrical contact wit ...
Redox Reactions Test Review
... 2. What is the common oxidation number for oxygen? What is the oxidation number for oxygen in
H2O2 (the exception)?
Redox #2 Oxidation Numbers
... Redox reactions are all about electrons being transferred from one substance to
another, so it would be useful if we had a system for keeping track of what gains
and what loses electrons, and how many electrons are involved.
We do - our record-keeping system is called Oxidation Numbers
9.1 Electron Transfer Reactions
... 3. The oxidation number of an element in its native state is
4. The oxidation number of a monatomic ion is the same as
5. O is usually – 2 (except for peroxides where it is – 1)
6. H is usually +1 (except for hydrides where it is – 1)
7. The periodic table can used as a guide for an ...
Oxidation Number Rules
... 3.) Balance atoms using H+ / OH- / H2O as needed:
acidic: H+ / H2O put water on side that needs O
basic: OH- / H2O put water on side that needs H but if there is no H involved then
put OH- on the side that needs the O in a 2:1 ratio 2OH- / H2O balance O with OH, double OH, add 1/2 water to
other sid ...
Predicting synthesis and decomposition reactions
... Determining Oxidation
5. In binary compounds (nonmetal +
nonmetal) the positive one is first and the
negative one is second
6. The sum of the oxidation numbers for all
atoms in a neutral compound is
7. The sum of the oxidation numbers in a
polyatomic ion is equal to the
... 2. Electron gain and loss
Electrochemistry is the study of the interchange of chemical and electrical energy.
Reactions with electron transfers are commonly called oxidation-reduction reactions (redox
Not all reactions involve an electron transfer – these reactions are refer ...
Oxidation-Reduction (Redox) Reactions
... and canceling duplicated species.
Step 5 (Only if the solution is under basic conditions): Add
enough OH- (to both sides) to neutralize any H+ ions.
Simplify by canceling duplicate species (if needed).
... A. Chemists assign a number to each element in a reaction called an _________________ state that allows him/her to
determine the electron flow in the reaction.
1. Even though they look like them, oxidation states are not _________ charges!
2. Oxidation numbers can be assigned to each atom in an elem ...
The oxidation state, often called the oxidation number, is an indicator of the degree of oxidation (loss of electrons) of an atom in a chemical compound. Conceptually, the oxidation state, which may be positive, negative or zero, is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic, with no covalent component. This is never exactly true for real bonds.The term ""oxidation"" was first used by Lavoisier to mean reaction of a substance with oxygen. Much later, it was realized that the substance on being oxidized loses electrons, and the use of the term ""oxidation"" was extended to include other reactions in which electrons are lost.Oxidation states are typically represented by small integers. In some cases, the average oxidation state of an element is a fraction, such as 8/3 for iron in magnetite (Fe3O4). The highest known oxidation state is reported to be +9 in the cation IrO+4, while the lowest known oxidation state is −5 for boron, gallium, indium, and thallium. The possibility of +9 and +10 oxidation states in platinum group elements, especially iridium(IX) and platinum(X), has been discussed by Kiselev and Tretiyakov.The increase in oxidation state of an atom through a chemical reaction is known as an oxidation; a decrease in oxidation state is known as a reduction. Such reactions involve the formal transfer of electrons, a net gain in electrons being a reduction and a net loss of electrons being an oxidation. For pure elements, the oxidation state is zero.There are various methods for determining oxidation states/numbers.In inorganic nomenclature the oxidation state is determined and expressed as an oxidation number represented by a Roman numeral placed after the element name.In coordination chemistry, oxidation number is defined differently from oxidation state.