Chemistry II: Chapter 19
The silver ion in a photochromic eyeglass lens darkens the lens when it reacts according to the equation Ag^+ +e^- --> Ag. The Silver acts as an...
oxidizing agent
Substances that accept electrons easily and are reduced are called...
oxidizing agents .
Which of the following is the most active reducing agent? Silver ion Calcium ion Sodium copper
Sodium
How does the number of electrons lost in oxidation compare with the number of electrons gained in the simultaneous reduction?
The two numbers are always equal.
In a balanced redox equation, how does the total number of reactant atoms compare with the total number of product atoms?
The two numbers are always equal.
In a balanced redox equation, how does the total charge of the reactants compare with the total charge of the products?
The two totals are always equal.
True or False? oxidation cannot occur without reduction.
True
Determine whether a reaction will occur or not for the following? Would Zn be oxidized by MnO2?
Yes
Determine whether a reaction will occur or not for the following? would H2 be oxidized by MnO2?
Yes
All of the following should be done in the process of balancing redox equations except... 1.) adjusting coefficients to balance atoms. 2.)adjusting coefficients in electron equations to balance numbers of electrons lost and gained. 3.) adjusting subscripts to balance atoms. 4.) writing two separate electron equations.
adjusting subscripts to balance atoms
oxidation or reaction? Fe^3+ + e- ---> Fe^2+
reduction
The titration of an acidic solution of FeSO4 with KMnO4. which produces Mn^2+ and Fe^3+, is an...
redox reaction
When Cu^2+ changes to Cu, copper is said to have been...
reduced because it gained 2e-
When Cr^3+ changes to cr, the chromium ion is said to have been...
reduced because it gained 3e-
The element sulfur can exist in all of the following oxidation states except ? -2, +4, +5, +6
+5
What is the oxidation state of phosphorus in PO4^3-
+5
Assign oxidation numbers and do half reactions
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Balanced ionic equation for the following redox reaction using the half - reaction method.
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the oxidation state of an oxygen atom in Na2O2 is...
-1
The oxidation number of uncombined oxygen is?
0
The sum of the oxidation numbers for all the atoms in a molecule is equal to?
0
The oxidation number of hydrogen atoms in compounds is usually?
+1
What is the oxidation state of sulfur in Al2S3?
+1
The oxidation state of the sulfur atom in SO3^2- is...
+4
What element displaces Pb^2+ ions from solution but is displaced by Fe metal when it is in ionic form?
Sn
The term oxidation arose early in the history of chemestry, when scientists obserbed elements combining with oxygen in combustion reactions. For example, S(s)+O2(g)---> SO2(g). In this reaction,
the oxygen is reduced and the sulfur is oxidized.
In the following reaction, which species is the oxidation agent? 2K+Br2---> 2K^+ +2Br^-
Br2
In the following reaction, which species is the reducing agent? Cl2+ 2Fe^2+ ----> 2Fe^3+ +2Cl^-
Fe^2+
When using the half-reaction method to balance redox reactions, to balance the hydrogen on the left side of a half - reaction, you must add...
H+ to the right side
When using half -reaction method to balance redox reactions, to balance the oxygen on the right side of a half- reaction, you must add...
H2O to the left side
Which of the following is the most active oxidizing agent?
Iron (III) iron
Determine whether a reaction will occur or not for the following? Would I2 be reduced by Cl^-?
No
Determine whether a reaction will occur or not for the following? Would NO3^- be reduced by Br^-?
No
Determine whether a reaction will occur or not for the following? Would Ni be oxidized by Cr^3+
No
Fe^2+ +Cl2--->Fe^3+ +Cl^- -Balanced for mass - Balanced for charge - Both -Neither
balanced for charge
To balance a redox equation, you must balance the number of atoms and the...
charge
During redox reactions, oxidizing agents...
decrease their oxidation number.
H2S is the compound primarily responsible for the odor of 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
The part of a reaction that involves only oxidation or only reduction is a...
half - reaction
Metals, hydrogen, and carbon are oxidized and are common...
reducing agents.
If oxidation is taking place, what is also occurring?
reduction
Redox reactions occur...
in air and in acidic and basic solutions.
During redox reactions, reducing agents...
increase their oxidation number.
oxidation or reduction? Na ---> Na+ + e-
oxidation
When an element undergoes combustion and loses electrons, the element is...
oxidized
When Fe changes to Fe^3+, iron is said to have been...
oxidized because it lost 3e-
Sodium hypochlorite, NaClO, is household bleach. It "removes" stains from clothing through a redox reaction in which the stain molecules are oxidized. Sodium hypochlorite acts as an...
oxidizing agent
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 disproportionation. It is an
oxidizing and reducing agent
Another name for an oxidation- reduction reaction is...
redox reaction
A substance that undergoes disproportionation 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 zink metal is placed in a solution of copper (II) sulfate, metallic copper precipitates because zinc is the...
stronger reducing agent
The oxidation number of a monatomic ion is equal to?
the charge of that ion
The sum of the oxidation numbers for all the atoms in a polyatomic ions is equal to?
the charge of that ion
In the reaction Zn(s)+ 2HCl(aq)---> H2(g) +ZnCl2(aq),
the zinc is oxidized and the hydrogen is reduced.
Determine whether a reaction will occur or not for the following? Would Hg2^2+ be reduced by Cu?
yes
