Call Now to Set Up Tutoring:

(888) 888-0446

AP Chemistry : Reactions and Equilibrium

Study concepts, example questions & explanations for AP Chemistry

Create An Account

All AP Chemistry Resources

6 Diagnostic Tests 225 Practice Tests Question of the Day Flashcards Learn by Concept

Example Questions

Example Question #1 : Oxidation Reduction Reactions

The following ReDox reaction takes place in acidic solution:

Fe²⁺ + Cr₂O₇^2– → Fe³⁺ + Cr³⁺

What is the sum of coefficients in this redox reaction?

Possible Answers:

Correct answer:

Explanation:

When you balance the redox reaction in acidic conditons, there are 6Fe²⁺, 1 Cr₂O₇^2–, 14 H⁺, 6 Fe³⁺, 2 Cr³⁺, and 7 H₂O. Don't forget to add the 1 in front of the Cr₂O₇^2–

Report an Error

Example Question #2 : Oxidation Reduction Reactions

For the following unbalanced redox reaction, how many electrons are transferred and which chemical species is being oxidized?

$PF_2I_{(l)}+Hg_{(l)}\rightarrow P_2F_4_{(g)}+Hg_2I_2_{(s)}$

Possible Answers:

Two electrons are transferred; P is oxidized

One electron is transferred; Hg is oxidized

Two electrons are transferred; Hg is oxidized

One electron is transferred; P is oxidized

Correct answer:

Two electrons are transferred; Hg is oxidized

Explanation:

To begin, we will need to separate the given reaction into the two half-reactions by identifying changes in oxidation number. In this case, mercury (Hg) and phosphorus (P) show a change in oxidation number. Mercury begins with an oxidation number of zero, and ends with an oxidation number of . Phosphorus begins with an oxidation number of and ends with an oxidation number of . Note that the oxidation numbers for fluorine and iodine reamain constant at for each.

Now we can begin to look at the half-reactions.

$PF_2I_{(l)}\rightarrow P_2F_4_{(g)}$

$Hg_{(l)}\rightarrow Hg_2I_2_{(s)}$

Balance the atoms.

$2PF_2I_{(l)}\rightarrow P_2F_4_{(g)}$

$2Hg_{(l)}\rightarrow Hg_2I_2_{(s)}$

Now balance the electrons. We know that each mercury atom loses one electron and each fluorine atom gains one electron.

$2PF_2I_{(l)}+2e^-\rightarrow P_2F_4_{(g)}$

$2Hg \rightarrow Hg_2I_2_{(s)}+2e^{-}$

We can see that two electrons are tranferred. To identify the element being oxidized, we must find the element that is losing electrons. In this case, mercury is being oxidized.

Report an Error

Example Question #1 : Balancing Oxidation Reduction Reactions

How many electrons are involved in the following reaction?

$MnO_4^-+ Fe^{2+} \rightarrow Fe^{3+}+Mn^{2+}$

Possible Answers:

5 e^-

3 e^-

2 e^-

1 e^-

4 e^-

Correct answer:

5 e^-

Explanation:

The common factor between 1 e^- and 5 e^- is 5. Therefore the number of electrons involved is 5 e^-.

Report an Error

Example Question #1 : Balancing Oxidation Reduction Reactions

How many electrons are involved in the following reaction?

$MnO_4^-+ I^-\rightarrow I_2+Mn^{2+}$

Possible Answers:

4 e^-

10 e^-

5 e^-

1 e^-

2 e^-

Correct answer:

10 e^-

Explanation:

The common factor between 2 e^- and 5 e^- is 10. Therefore the number of electrons involved is 10 e^-.

Report an Error

Example Question #1 : Balancing Oxidation Reduction Reactions

What is the balanced coefficient on OH^- for the following reaction:

$Br^- + MnO_4^- \rightarrow MnO_2 + BrO_3^-$ (under basic conditions)

Possible Answers:

Correct answer:

Explanation:

Add them together:

$3 H_2 O + Br^- + 2 MnO_4^- + 8 H^+ + 6 e^- \rightarrow 2 MnO_2 + BrO_3^- + 6 H^+ + 4 H_2 O + 6 e^-$

Simplify:

$Br^- + 2 MnO_4^- + 2 H^+ \rightarrow 2 MnO_2 + BrO_3^- + H_2 O$

Add Hydroxides to each side to counter H⁺_.

$Br^- + 2 MnO_4^- + 2 H_2 O \rightarrow 2 MnO_2 + BrO_3^- + H_2 O+2 OH^-$

Simplify:

$Br^- + 2 MnO_4^- + H_2 O \rightarrow 2 MnO_2 + BrO_3^- +2 OH^-$

Report an Error

Example Question #4 : Oxidation Reduction Reactions

What is the sum of all the balanced coefficients in the following reaction:

$O_2 + Sb \rightarrow H_2 O_2 + SbO_2^-$ (basic conditions)

Possible Answers:

Correct answer:

Explanation:

Add the equations together

$2Sb+4H_2 O + 3 O_2 + 6 H^+ + 6e^- \rightarrow 2SbO_2^-+8H^++3 H_2 O_2 + 6e^-$

Simplify

$2Sb+4H_2 O+3 O_2 \rightarrow 2SbO_2^-+2H^++3H_2 O_2$

Add 2 OH^- to each side to cancel out the H⁺_.

$2Sb+4H_2 O+3 O_2 + 2 OH^- \rightarrow 2SbO_2^-+2H_2 O+3H_2 O_2$

Simplify:

$2Sb+2 H_2 O+3 O_2 + 2 OH^- \rightarrow 2SbO_2^-+3H_2 O_2$

Report an Error

Example Question #1 : Half Reactions

$Fe_{(s)} + 2HCl_{(aq)} \rightarrow FeCl_{2(aq)} + H_{2(g)}$

For the redox reaction shown, which of the following half reactions occurs in the anode?

Possible Answers:

$2H_{2} + 2e^{-} \rightarrow H_{2}$

$Fe \rightarrow Fe^{3+} + 3e^{-}$

$Fe \rightarrow Fe^{2+} + 2e^{-}$

$Fe^{2+} + 2e^{-} \rightarrow Fe$

Correct answer:

$Fe \rightarrow Fe^{2+} + 2e^{-}$

Explanation:

Recall that oxidation always occurs at the anode (in both the electrochemical and galvanic cells). loses two electrons in this case to become $Fe^{2+}$ . The presence of $Fe^{2+}$ is hinted by the ionic compound FeCl_2 _.

Report an Error

Example Question #1 : Oxidation State

When is the oxidation number of H (-1)?

Possible Answers:

Only when it is bonded to Chlorine

Only when it is bonded to Flourine

Never

When it is bonded to a less electronegative element

When it is bonded to a more electronegative element

Correct answer: When it is bonded to a less electronegative element

Explanation:

We typically think of Hydrogen as having an oxidation number of +1. However when it is bonded to a less electronegative element such as Na it is actually assigned an oxidation number of -1.

Report an Error

Example Question #1 : Oxidation State

What is the oxidation number of manganese in KMnO_4 ?

Possible Answers:

Correct answer:

Explanation:

KMnO_4

Potassium always has an oxidation state of , while oxygen always has an oxidation state of . Since we have four oxygens, there is a total charge of from them.

The most important rule of oxidation numbers is that their sum must equal the charge on the molecule. In this compound, we have (+1)+4(-2)+Mn=0 .

(+1)-8+Mn=0

-7+Mn=0

Mn=+7

Manganese needs to cancel out the charge from potassium and oxygen in order to give us a neutral compound.

Report an Error

Example Question #111 : Reactions And Equilibrium

What is the oxidation number of chlorine in perchlorate?

Possible Answers:

Correct answer:

Explanation:

Perchlorate is a complex ion with the formula ClO_4^- .

The most important rule for oxidation number is that the sum of the oxidation states of the atoms must equal the overall molecular charge.

(Cl)+4(O)=-1

This compound has four oxygens, which always have a oxidation state.

(Cl)+4(-2)=-1

(Cl)-8=-1

Chlorine usually has an oxidation state of , but in this case it must balance out the oxygens.

Cl=+7

Chlorine must be .

Report an Error

View AP Chemistry Tutors

Garth
Certified Tutor

View AP Chemistry Tutors

Alejandro
Certified Tutor

Kennesaw State University, Bachelor of Science, Computer Software Engineering.

View AP Chemistry Tutors

Siddharth
Certified Tutor

University of Petroleum and Energy Studies and, Masters in Business Administration, Aviation Management.

All AP Chemistry Resources

6 Diagnostic Tests 225 Practice Tests Question of the Day Flashcards Learn by Concept

Popular Subjects

Physics Tutors in Atlanta, Statistics Tutors in Dallas Fort Worth, ISEE Tutors in San Diego, Chemistry Tutors in San Diego, Statistics Tutors in Washington DC, Chemistry Tutors in Chicago, English Tutors in Chicago, LSAT Tutors in Boston, French Tutors in Washington DC, Algebra Tutors in Houston

Popular Courses & Classes

ACT Courses & Classes in New York City, SSAT Courses & Classes in New York City, LSAT Courses & Classes in Miami, ISEE Courses & Classes in San Diego, GMAT Courses & Classes in New York City, ACT Courses & Classes in Atlanta, LSAT Courses & Classes in Washington DC, LSAT Courses & Classes in Philadelphia, ISEE Courses & Classes in Philadelphia, SSAT Courses & Classes in Denver

Popular Test Prep

ISEE Test Prep in Seattle, SSAT Test Prep in Houston, GMAT Test Prep in Dallas Fort Worth, ACT Test Prep in Atlanta, MCAT Test Prep in New York City, SSAT Test Prep in Boston, SSAT Test Prep in San Francisco-Bay Area, SAT Test Prep in Denver, ISEE Test Prep in Phoenix, ISEE Test Prep in Philadelphia

DMCA Complaint

If you believe that content available by means of the Website (as defined in our Terms of Service) infringes one or more of your copyrights, please notify us by providing a written notice (“Infringement Notice”) containing the information described below to the designated agent listed below. If Varsity Tutors takes action in response to an Infringement Notice, it will make a good faith attempt to contact the party that made such content available by means of the most recent email address, if any, provided by such party to Varsity Tutors.

Your Infringement Notice may be forwarded to the party that made the content available or to third parties such as ChillingEffects.org.

Please be advised that you will be liable for damages (including costs and attorneys’ fees) if you materially misrepresent that a product or activity is infringing your copyrights. Thus, if you are not sure content located on or linked-to by the Website infringes your copyright, you should consider first contacting an attorney.

Please follow these steps to file a notice:

You must include the following:

A physical or electronic signature of the copyright owner or a person authorized to act on their behalf; An identification of the copyright claimed to have been infringed; A description of the nature and exact location of the content that you claim to infringe your copyright, in \ sufficient detail to permit Varsity Tutors to find and positively identify that content; for example we require a link to the specific question (not just the name of the question) that contains the content and a description of which specific portion of the question – an image, a link, the text, etc – your complaint refers to; Your name, address, telephone number and email address; and A statement by you: (a) that you believe in good faith that the use of the content that you claim to infringe your copyright is not authorized by law, or by the copyright owner or such owner’s agent; (b) that all of the information contained in your Infringement Notice is accurate, and (c) under penalty of perjury, that you are either the copyright owner or a person authorized to act on their behalf.

Send your complaint to our designated agent at:

Charles Cohn Varsity Tutors LLC
101 S. Hanley Rd, Suite 300
St. Louis, MO 63105

Or fill out the form below:

Do not fill in this field

Contact Information

* Full legal name

Company name

* Phone number

* Email address

Address

* Address1

Address2

* City

* State

* Zipcode

* Country

Complaint Details

* URL of copyrighted work (where your original material is located)

* Please describe the copyrighted work so that it may be easily identified

I am the owner, or an agent authorized to act on behalf of the owner of an exclusive right that is allegedly infringed.

I have a good faith belief that the use of the material in the manner complained of is not authorized by the copyright owner, its agent, or the law.

This notification is accurate.

I acknowledge that there may be adverse legal consequences for making false or bad faith allegations of copyright infringement by using this process.

* Signature (your digital signature is legally binding)

HIGH SCHOOL

GRADUATE SCHOOL

K-8

Search 50+ Tests

math tutoring

science tutoring

foreign languages

elementary tutoring

other

Search 350+ Subjects

AP Chemistry : Reactions and Equilibrium

Study concepts, example questions & explanations for AP Chemistry

All AP Chemistry Resources

Example Questions

Example Question #1 : Oxidation Reduction Reactions

Example Question #2 : Oxidation Reduction Reactions

Example Question #1 : Balancing Oxidation Reduction Reactions

Example Question #1 : Balancing Oxidation Reduction Reactions

Example Question #1 : Balancing Oxidation Reduction Reactions

Example Question #4 : Oxidation Reduction Reactions

Example Question #1 : Half Reactions

Example Question #1 : Oxidation State

Example Question #1 : Oxidation State

Example Question #111 : Reactions And Equilibrium

All AP Chemistry Resources

Report an issue with this question

DMCA Complaint

Contact Information

Address

Complaint Details

Email address:
Your name:
Feedback: