CHEM CHAPTER 6

The species that is reduced is the ________; the species that is oxidized is the _______.

oxidizing agent / reducing agent

The sum of the oxidation numbers for the atoms in an uncharged formula is equal to _____.

zero and the overall charge on the species

One of the ways that dry cell batteries differ from voltaic cell batteries in that the electrolytic solution in a dry cell is ______.

a semi-solid

Determine if the following species are oxidized or reduced. Cu2+ + e- → Cu+

reduced

Determine if the following species are oxidized or reduced. F + e- → F-

reduced

Determine if the given species is oxidized or reduced in this reaction: 2 K(s) + F2(g) \rightarrow→ 2 KF(s) F in F2(g)

reduced

Determine if the given species is oxidized or reduced in this reaction: 4 Al(s) + 3 O2(g) \rightarrow→ 2 Al2O3(s) O in O2(g)

reduced

Determine if the given species is oxidized or reduced in this reaction: ZnO(s) + C(s) → Zn(l) + CO(g)

reduced

Give the oxidation number of the following atom: S in Na2SO4

+6

Give the oxidation number of the following atom: O in CO2

-2

Give the oxidation number of the following atom: O in Na2SO4

-2

Give the oxidation number of the following atom: P in P4

0

The oxidation number of a pure element is ______.

0

Give the oxidation number of the following atom: H in H2O2

+1

Give the oxidation number of the following atom: Na in Na2SO4

+1

Give the oxidation number of the following atoms. Li in LiCl

+1

Give the oxidation number of the following atom: C in CO2

+4

The sum on the oxidation numbers for the atom(s) in a monatomic or polyatomic ion is equal to _____.

the overall charge on the species

Complete the half-reactions for the following redox reaction: 2 Mg(s) + O2(g) \rightarrow→ 2 MgO(s) O2 + ____ \rightarrow→ 2 O2-

4e-

Oxidation-reduction reactions are easier to understand, and easier to balance, if we break them into separate oxidation and reduction reactions, called half reactions. It is important to note that the total number of electrons created in the oxidation half reaction is identical to the number used in the reduction half reaction. Complete the half-reactions for the following redox reaction: 2 Mg(s) + O2(g) \rightarrow→ 2 MgO(s) 2 Mg \rightarrow→ 2 Mg2+ + ____

4e-

For molecules containing carbon and hydrogen, complete combustion yields CO2 and H2O. When insufficient oxygen is present, ______ may also form as a combustion product.

CO

List all of the products formed for the complete combustion of dimethyl sulfide: CH3SCH3(g) + O2(g) \rightarrow→

CO2(g), H2O(g), SO2(g)

Determine if the following reaction is a redox reaction. If it is, identify the oxidizing agent and the reducing agent. 2 Na(s) + 2 H2O(l) \rightarrow→ 2 NaOH(aq) + H2(g) Identify the Oxidizing agent

H2O(l)

Determine if the following reaction is a redox reaction. If it is, identify the oxidizing agent and the reducing agent. 2 Na(s) + 2 H2O(l) \rightarrow→ 2 NaOH(aq) + H2(g) Identify the Reducing agent

Na(s)

In a discharging battery, oxidation, the loss of electrons from the metal or metal ion, occurs at the _______, which then carries a _______ charge.

anode / negative

Each electrode is bathed in electrolyte solution in its own half-cell. As the electrons are allowed to flow between the electrodes, cations of the anodic metal _________ which draws anions towards it from the ___X____.

are released into solution

Oxidation and reduction always occur simultaneously, as electrons are transferred from one ____ to another.

atom or ion

In a discharging battery, reduction, the gain of electrons by the metal ion, occurs at the _______, which then carries a _______ charge.

cathode / positive

A battery is a device that converts ______ energy into ______ energy using redox reactions.

chemical / electrical

A ______ reaction is one in which multiple elements or compounds come together to form a single new compound.

combination

Classify the reaction according to type: 2 NO(g) + O2(g) \rightarrow→ 2 NO2(g)

combination

Classify the reaction according to type: B2O3(s) + 3 H2O(l) \rightarrow→ 2 B(OH)3(s)

combination

A ______ reaction is a rapid redox reaction accompanied by release of heat and light. The oxidizing agent is usually oxygen.

combustion

Determine if electron transfer is partial or complete: 2 Li(s) + S(s) \rightarrow→ 2 Li2S(s)

complete

The flow of electrons through an electrical conductor is the _______.

current

A ______ reaction is a reaction in which one compound is converted into two or more compounds.

decomposition

Classify the reaction according to type: 2 NaNO3(s) \rightarrow→ 2 NaNO2(s) + O2(g)

decomposition

All decomposition reactions are redox reactions.

false

A battery is comprised of one or more electrochemical cells called _______ cells. The electrodes of these cells attach to the terminals of the battery. Connecting the terminals with an electronic device allows current to flow from one electrode to the other.

galvanic or voltaic

When uncharged metal atoms react with oxygen to form metal oxides, electrons are transferred from the ______ atoms to the _____ atoms to form the ions that make up the metal oxides.

metal / oxygen

Determine if the following reaction is a redox reaction. If it is, which substance is oxidized and which is reduced? HCl(aq) + NH3(aq) \rightarrow→ NH4Cl(aq) Is this a Redox reaction?

no

Determine if the following species are oxidized or reduced. Ca → Ca2+ + 2e-

oxidized

Determine if the following species are oxidized or reduced. K → K+ + e-

oxidized

Determine if the given species is oxidized or reduced in this reaction: 2 K(s) + F2(g) → 2 KF(s) K in K(s)

oxidized

Determine if the given species is oxidized or reduced in this reaction: 4 Al(s) + 3 O2(g) \rightarrow→ 2 Al2O3(s) Al in Al(s)

oxidized

Determine if the given species is oxidized or reduced in this reaction: ZnO(s) + C(s) → Zn(l) + CO(g) C in C(s)

oxidized

If an element's oxidation number increases in a chemical reaction, the reaction is an oxidation-reduction reaction and the element was _______.

oxidized

Atoms that lose electrons during a chemical reaction are ______ in the process. Whereas atoms that gain electrons are ______.

oxidized / reduced

Determine if electron transfer is partial or complete: 2 H2(g) + O2(g) \rightarrow→ 2 H2O(l)

partial

Oxidation-reduction reactions between two nonmetal elements occur with _______ electron transfer...

partial

The atom that attracts the electrons to a greater degree ends up with a ______ charge in the molecular product, ...

partial negative

... whereas the atom that lets go of an electron more freely ends up with a ______ charge.

partial positive

... resulting in formation of ______ redox products.

polar covalent

The ______ reaction only occurs if an electrical conductor connects the anode and cathode allowing the electrons to flow.

redox

Each electrode is bathed in electrolyte solution in its own half-cell. As the electrons are allowed to flow between the electrodes, cations of the anodic metal ____X_____ which draws anions towards it from the _______.

salt bridges and electrolytes

A ______ reaction occurs when atoms of an element replace the atoms of another element in a compound.

single-displacement

Classify the reaction according to type: 3 H2(g) + WO3(s) \rightarrow→ W(s) + 3 H2O(l)

single-displacement

Over time the anode becomes _______ and the cathode becomes _______ until finally the battery dies. becomes dead.

smaller / larger

Electrolysis is a process whereby spontaneous redox reactions are reversed through the application of directed electric current.

true

Some combination reactions are also redox reactions.

true

The principle of electrolysis is used in rechargeable batteries, since electric current is used to reverse the preferred redox reaction, thereby restoring the original electrodes.

true

The force with which the electrons flow is the _______.

voltage

Determine if the following reaction is a redox reaction. If it is, identify the oxidizing agent and the reducing agent. 2 Na(s) + 2 H2O(l) \rightarrow→ 2 NaOH(aq) + H2(g) Is this a Redox Reaction?

yes