We are open Saturday and Sunday!

Call Now to Set Up Tutoring:

(888) 888-0446

AP Chemistry : Balancing Equations

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 : Balancing Equations

Balance the following equation:

NaOH + H₂SO₄ → H₂O + Na₂SO₄

Possible Answers:

2 NaOH + H₂SO₄ → H₂O + Na₂SO₄

4 NaOH + H₂SO₄ → 2 H₂O + 2 Na₂SO₄

2 NaOH + H₂SO₄ → 2 H₂O + Na₂SO₄

4 NaOH + 2 H₂SO₄ → 4 H₂O + 2 Na₂SO₄

NaOH + H₂SO₄ → H₂O + Na₂SO₄

Correct answer:

2 NaOH + H₂SO₄ → 2 H₂O + Na₂SO₄

Explanation:

Balancing equations:

there is 1 NaOH and 1 H₂SO₄ in the reactants; and 1 H₂O and 1 Na₂SO₄ in the products

steps:

1) balance the Na first; get 2 NaOH

2) balance H next; get 1 H₂SO4, 2 H₂O

3) check to make sure that O and S balance

Report an Error

Example Question #11 : Balancing Reactions

_Fe₂O₃ + _HCl ⇌ _FeCl₃ + _H₂O

The Following question will be based on the unbalanced reaction above

For the reaction above to be balanced what coefficient should be in front of the compound HCl?

Possible Answers:

Correct answer:

Explanation:

Balancing reactions is best acheived by using a stepwise approach. It is useful to work through each atom making sure it is present in a balanced fashion on both sides of the equation. Starting with Fe, Fe₂O₃is the only molecule with Fe present on the left side of the equation and FeCl₃ is the only molecule with Fe present on the right side of the equation. Thus the molar ratio of Fe₂O₃to FeCl₃ must be 1:2. Moving on to O, the O on the left side of the equation exists as Fe₂O₃ and H₂O on the right. The molar ratio of Fe₂O₃to H₂O is therefore 1:3. Cl exists in HCl on the left and FeCl₃on the right. Thus the molar ratio of HCl to FeCl₃ must be 3:1. To ensure that these molar ratios are maintaned the balanced formula is then determined to be Fe₂O₃ + 6HCl -> 2FeCl₃ + 3H₂O

Report an Error

Example Question #2 : Balancing Equations

Balance the following equation:

FeCl₃+ NOH₅→ Fe(OH)₃ + NH₄Cl

Possible Answers:

3 FeCl₃ + 3 NOH₅ → 2 Fe(OH)₃ + 4 NH₄Cl

2 FeCl₃ + 3 NOH₅ → 2 Fe(OH)₃ + 3 NH₄Cl

2 FeCl₃ + 4 NOH₅ → Fe(OH)₃ + 6 NH₄Cl

FeCl₃ + 3 NOH₅ → Fe(OH)₃ + 3 NH₄Cl

3 FeCl₃ + 3 NOH₅ → 3 Fe(OH)₃ + 3 NH₄Cl

Correct answer:

FeCl₃ + 3 NOH₅ → Fe(OH)₃ + 3 NH₄Cl

Explanation:

The first thing to do is to balance the Cl (3 on the left; one on the right) ← add 3 for NH₄Cl

Now, there are 3 N on the right and only one on the left; add a 3 to the NOH₅

Check to see that the Fe, H, and O balance, which they do

Report an Error

Example Question #1 : Balancing Equations

After the following reaction is balanced, how many moles of H₂O can 4 moles of C₂H₆produce?

__C₂H₆(s) + ___O₂(g) → ___H₂O(l) + ___CO₂(g)

Possible Answers:

Correct answer:

Explanation:

The reaction balances out to 2C₂H₆(s) + 7O₂(g) → 6H₂O(l) + 4CO₂(g). For every 2 moles of C₂H₆ you can produce 6 moles of H₂O. Giving you a total production of 12 moles when you have 4 moles of C₂H₆.

Report an Error

Example Question #3 : Stoichiometry

Consider the following reaction:

$KMnO_{4} + HCl \rightarrow KCl + MnCl_{2} + H_{2}O + Cl_{2}$

When the equation is balanced, what will be the coefficient in front of HCl?

Possible Answers:

Correct answer:

Explanation:

When balancing equations, the goal is to make sure that the same atoms, in both type and amount, are on both the reactant and product side of the equation. A helpful approach is to write down the number of atoms already on both sides of the unbalanced equation. This way, you can predict which compounds need to be increased on which side in order to balance the equation. It also helps to balance oxygen and hydrogen last in the equation.

In this reaction, we can balance as follows.

Reactants: 1K, 1Mn, 1Cl, 4O, 1H

Products: 1K, 1Mn, 5Cl, 1O, 2H

So, we will need to increase H₂O and HCl. The final balanced equation is written below.

$2KMnO_{4} + 16HCl \rightarrow 2KCl + 2MnCl_{2} + 8H_{2}O + 5Cl_{2}$

Report an Error

Example Question #1 : Balancing Equations

Balance the following chemical equation.

$NaOH + FeCl_{3} \rightarrow NaCl + Fe(OH)_3$

Possible Answers:

$3NaOH+2FeCl_3\rightarrow 2NaCl+2Fe(OH)_3$

$3NaOH+FeCl_3\rightarrow 3NaCl+3Fe(OH)_3$

$3NaOH + FeCl_{3} \rightarrow NaCl + Fe(OH)_3$

$NaOH + FeCl_{3} \rightarrow 3NaCl + Fe(OH)_3$

$3NaOH + FeCl_{3} \rightarrow 3NaCl + Fe(OH)_3$

Correct answer:

$3NaOH + FeCl_{3} \rightarrow 3NaCl + Fe(OH)_3$

Explanation:

To balance an equation, we need to make sure there is the same amount of elements to the left of the arrow as there is to the right. We also need all the charges to balance out. We notice right away that there are three chlorine atoms on the left, but only one on the right.

$NaOH + FeCl_{3} \rightarrow NaCl + Fe(OH)_3$ (1Na, 1O, 1H, 1Fe, 3Cl : 1Na, 3O, 3H, 1Fe, 1Cl)

We can solve this by multiplying NaCl by three.

$NaOH + FeCl_{3} \rightarrow 3NaCl + Fe(OH)_3$ (1Na, 1O, 1H, 1Fe, 3Cl : 3Na, 3O, 3H, 1Fe, 3Cl)

This causes us to have an imbalance of sodium, which we can correct by manipulating NaOH.

$3NaOH + FeCl_{3} \rightarrow 3NaCl + Fe(OH)_3$ (3Na, 3O, 3H, 1Fe, 3Cl : 3Na, 3O, 3H, 1Fe, 1Cl)

This is the final balanced equation. Note that it is usually easiest to manipulate oxygen and hydrogen last, since they are often involved in multiple molecules.

Report an Error

Example Question #32 : Chemical Reactions

Calcium hydroxide is treated with hydrochloric acid to produce water and calcium chloride. Write a balanced chemical reaction that describes this process.

Possible Answers:

$2Ca(OH)_{2} + HCl \rightarrow H_{2}O + 2CaCl_{2}$

$Ca(OH)_{2} + HCl \rightarrow H_{2}O + CaCl_{2}$

$Ca(OH)_{3} + 3HCl \rightarrow 3H_{2}O + CaCl_{3}$

$CaOH + HCl \rightarrow H_{2}O + CaCl$

$Ca(OH)_{2} + 2HCl \rightarrow 2H_{2}O + CaCl_{2}$

Correct answer:

$Ca(OH)_{2} + 2HCl \rightarrow 2H_{2}O + CaCl_{2}$

Explanation:

Calcium is in the second group of the periodic table, and is therefore going to have a $\small +2$ oxidation number. Hydroxide ions have a $\small -1$ charge. Calcium hydroxide will have the formula $\small Ca(OH)_2$ .

Chloride ions have a $\small -1$ charge and hydrogen ions have a $\small +1$ charge. The formula for hydrochloric acid is $\small HCl$ .

On the products side, water has the formula $\small H_2O$ and calcium chloride has the formula $\small CaCl_2$ .

Now that we know all of the formulas, we can write our reaction:

$Ca(OH)_2+HCl\rightarrow H_2O+CaCl_2$

In order to balance the chloride atoms, we need to add coefficients.

$Ca(OH)_2+2HCl\rightarrow 2H_2O+CaCl_2$

Report an Error

Example Question #4 : Balancing Equations

Consider the following unbalanced equation for the combustion of propane, $C_3H_8$ :

$C_3H_{8\hspace{1 mm}(g)}+O_{2\hspace{1 mm}(g)}\rightarrow CO_{2\hspace{1 mm}(g)}+H_2O_{(l)}$

If you were to combust one mole of propane, how many moles of water would you produce?

Possible Answers:

$5 mol\ H_2O$

$3 mol\ H_2O$

$2 mol\ H_2O$

$1 mol\ H_2O$

$4 mol\ H_2O$

Correct answer:

$4 mol\ H_2O$

Explanation:

Begin by balancing the equation. There are many ways to do this, but one method that is particularly useful is to assume that you have 1 mole of your hydrocarbon (propane), and balance the equation from there. It may be necessary to manipulate an equation further if you end up with fractions, but all you will need to do is multiply by an integer if that is the case.

First, we will balance the carbons. There are three carbons in propane, so we will make sure there are three carbons on the right side of the arrow as well:

$C_3H_8 + O_2 \rightarrow 3CO_2 + H_2O$

This is not complete. We will next balance the hydrogens. There are eight hydrogens on the left side of the equation, so:

$C_3H_8 + O_2 \rightarrow 3CO_2 + 4H_2O$

The last step is to balance the oxygens on the left and right side of the equation

$C_3H_8 + 5O_2 \rightarrow 3CO_2 + 4H_2O$

Our equation is balanced and all coefficients are integers. If we begin with one mole of propane, we will produce four moles of water.

Report an Error

Example Question #11 : Balancing Chemical Equations

Consider the following unbalanced equation:

$Fe+Cl_2\rightarrow FeCl_3$

How many grams of solid iron are needed to make 36.0g of $FeCl_3$ ? Assume that chlorine is in excess.

Possible Answers:

$18.6\hspace{1 mm}g\hspace{1 mm}Fe$

$36.0\hspace{1 mm}g\hspace{1 mm}Fe$

$8.27\hspace{1 mm}g\hspace{1 mm}Fe$

$2.22*10^{-1}g\ Fe$

$12.4\hspace{1 mm}g\hspace{1 mm}Fe$

Correct answer:

$12.4\hspace{1 mm}g\hspace{1 mm}Fe$

Explanation:

$Fe+Cl_2\rightarrow FeCl_3$

First, we will balance the equation:

$2Fe+3Cl_2\rightarrow 2FeCl_3$

Since chlorine is in excess, we know that the limiting reagent is iron.

$36.0\hspace{1 mm}g\hspace{1 mm}FeCl_3\times\frac{1\hspace{1 mm}mole\hspace{1 mm}FeCl_3}{162.2\hspace{1 mm}g\hspace{1 mm}FeCl_3}\times\frac{2\hspace{1 mm}moles\hspace{1 mm}Fe}{2\hspace{1 mm}moles\hspace{1 mm}FeCl_3}\times\frac{55.845\hspace{1 mm}g\hspace{1 mm}Fe}{1\hspace{1 mm}mole\hspace{1 mm}Fe}=12.4\hspace{1 mm}g\hspace{1 mm}Fe$

Report an Error

Example Question #1 : Balancing Equations

$S + HNO_{3} \rightleftharpoons H_{2}SO_{4} + NO_{2} + H_{2}O$

In the balanced version of the preceding equation, what is the coefficient of nitrogen dioxide?

Possible Answers:

Correct answer:

Explanation:

In the balanced version of the equation:

$S + 6HNO_{3} \rightleftharpoons H_{2}SO_{4} + 6NO_{2} + 2H_{2}O$

Nitrogen dioxide's coefficient is 6 in order to balance the 6 moles of nitrogen provided by the 6 moles of nitric acid on the equation's left side.

Report an Error

View AP Chemistry Tutors

Steven
Certified Tutor

University of Waterloo, Bachelor of Science, Chemical Engineering. McMaster University, Master of Science, Chemical Engineeri...

View AP Chemistry Tutors

James
Certified Tutor

University of Georgia, Bachelor in Arts, Political Science and Government.

View AP Chemistry Tutors

Melodi
Certified Tutor

Case Western Reserve University, Bachelor of Science, Computer Science.

All AP Chemistry Resources

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

Popular Subjects

Statistics Tutors in Denver, Calculus Tutors in Phoenix, ISEE Tutors in Houston, Calculus Tutors in Boston, ACT Tutors in Denver, Statistics Tutors in Los Angeles, Chemistry Tutors in San Francisco-Bay Area, English Tutors in Chicago, MCAT Tutors in Atlanta, Reading Tutors in San Francisco-Bay Area

Popular Courses & Classes

SAT Courses & Classes in New York City, Spanish Courses & Classes in Miami, SSAT Courses & Classes in Chicago, GMAT Courses & Classes in Philadelphia, ACT Courses & Classes in Boston, GMAT Courses & Classes in Washington DC, SSAT Courses & Classes in Houston, MCAT Courses & Classes in Los Angeles, ISEE Courses & Classes in Atlanta, GRE Courses & Classes in Seattle

Popular Test Prep

SAT Test Prep in San Francisco-Bay Area, LSAT Test Prep in Phoenix, MCAT Test Prep in Denver, ACT Test Prep in Miami, MCAT Test Prep in Los Angeles, GRE Test Prep in Miami, LSAT Test Prep in Atlanta, SAT Test Prep in Houston, ISEE Test Prep in Houston, GMAT 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 : Balancing Equations

Study concepts, example questions & explanations for AP Chemistry

All AP Chemistry Resources

Example Questions

Example Question #1 : Balancing Equations

Example Question #11 : Balancing Reactions

Example Question #2 : Balancing Equations

Example Question #1 : Balancing Equations

Example Question #3 : Stoichiometry

Example Question #1 : Balancing Equations

Example Question #32 : Chemical Reactions

Example Question #4 : Balancing Equations

Example Question #11 : Balancing Chemical Equations

Example Question #1 : Balancing Equations

All AP Chemistry Resources

Report an issue with this question

DMCA Complaint

Contact Information

Address

Complaint Details

Email address:
Your name:
Feedback: