oxidation-reduction chapter
the element sulfur can exist in all of the following oxidation states except
+5
The charge of a noxygen atom in Na2O2 is
-1
the oxidation number of oxygen atoms in compounds is usually
-2
the oxidation number of uncombined iodine is
0
the sum of the oxidation numbers for all the atoms in a molecule is equal to
0
what is the reduction half-reaction for the following redox reactoin? Zn+HgO-->ZnO+Hg
Hg^2+ +2e^- --> Hg
When using the half-reaction method, you balance redox reactions in basic solutions, you must add
OH^- ions and water
what is the oxidation half-reaction for the following redox reaction? Zn+HgO --> ZnO +Hg?
Zn-->Zn^2+ + 2e^-
When using the half-reaction method to balance redox reactions, once you have the formula equation and ionic equation, the next step is to
assign oxidation numbers
To balance a redox reaction, you must balance the number of atoms and the
charge
H2S is the compound primarily responsible for the odor in skunk spray. When H2S is oxidized, the odor
decreases
Both positive and negative charges arise in redox reactions, but the only particles that move from one reactant to another are
electrons
When using the half-reaction method to balance redox reactions, to balance the oxygen on the right side of the half-reaction, you must add
electrons to the left side
the part of a reaction that involves only oxidation or reduction is
half-reaction
Redox reactions occur
in the air and in acidic and neutral solutions
When an element undergoes combustion and loses electrons, the
oxidized
The silver ion in a photochromic eyeglass lens darkens the lens when it racts according to the equation Ag^+ +e^- -->Ag. The silver ion acts as an
oxidizing agent
Substances that accept electrons easily and are reduced are called
oxidizing agents
To repel large predators, a bombardier beetle uses hydrogen peroxide in a redox reaction that produces a hot, smelly liquid. Hydrogen peroxide is a substance that undergoes disproportioation. It is an
oxidizing and reducing agent
The titration of an acidic solution of FeSO4, with KMnO4, which produces Mn^2+ ions and Fe^3+ ions is an
redox reaction
another name for an oxidation-reduction action is
redox reaction
when cr^2+ changes to cr^0, the chromium ion is said to have been
reduced because it gained 3e^-
Sodium hypochlorite, NaOCl, is household bleach. It removes stains from clothing through a redox reaction in which the stain molecules are oxidized. Sodium hypochlorite acts as an
reducing agent
Metals, hydrogen and carbon are oxidized and are common
reducing agents
if oxidation is taking place, what must also be occurring?
reduction
A substance that undergoes disproportion is
self-oxidizing and self-reducing
When a piece of copper is wrapped around a piece of iron wire and placed in a warm, humid environment, the iron is oxidized because iron is the
stronger reducing agent
When a piece of zinc metal is placed in a solution of copper(II) sulfate, metallic copper precipitates because zinc is the
stronger reducing agent
the sum of the oxidation numbers for all atoms in a polyatomic ion is equal to
the charge of that ion
the term oxidation arose early in the history of chemistry, when scientists observed elements combining with oxygen in combustion reactions. for example, S+02 --> SO2. In this reaction,
the oxygen is reduced and the sulfure is oxidized