stoichiometry homework

Chemistry Steps

General Chemistry

Stoichiometry.

This is a comprehensive, end-of-chapter set of practice problems on stoichiometry that covers balancing chemical equations, mole-ratio calculations, limiting reactants, and percent yield concepts. 

The links to the corresponding topics are given below.

• The Mole and Molar Mass
• Molar Calculations
• Percent Composition and Empirical Formula
• Stoichiometry of Chemical Reactions

Limiting Reactant

• Reaction/Percent Yield
• Stoichiometry Practice Problems

Balance the following chemical equations:

a) HCl + O 2 → H 2 O + Cl 2

b) Al(NO 3 ) 3 + NaOH → Al(OH) 3 + NaNO 3

c) H 2 + N 2 → NH 3

d) PCl 5 + H 2 O → H 3 PO 4 + HCl

e) Fe + H 2 SO 4 → Fe 2 (SO 4 ) 3 + H 2

f) CaCl 2 + HNO 3 → Ca(NO 3 ) 2 + HCl

g) KO 2 + H 2 O → KOH + O 2 + H 2 O 2

h) Al + H 2 O → Al 2 O 3 + H 2

i) Fe + Br 2 → FeBr 3

j) Cu + HNO 3 → Cu(NO 3 ) 2 + NO 2 + H 2 O

k) Al(OH) 3 → Al 2 O 3 + H 2 O

l) NH 3 + O 2 → NO + H 2 O

m) Ca(AlO 2 ) 2 + HCl → AlCl 3 + CaCl 2 + H 2 O

n) C 5 H 12 + O 2 → CO 2 + H 2 O

o) P 4 O 10 + H 2 O → H 3 PO 4

p) Na 2 CrO 4 + Pb(NO 3 ) 2 → PbCrO 4 + NaNO 3

q) MgCl 2 + AgNO 3 → AgCl + Mg(NO 3 ) 2

r) KClO 3 → KClO 4 + KCl

s) Ca(OH) 2 + H 3 PO 4 → Ca 3 (PO 4 ) 2 + H 2 O

Consider the balanced equation:

C 5 H 12 + 8 O 2 → 5CO 2 + 6H 2 O

Complete the table showing the appropriate number of moles of reactants and products.

How many grams of CO 2  and H 2 O are produced from the combustion of 220. g of propane (C 3 H 8 )?

C 3 H 8 (g) + 5O 2 (g) → 3CO 2 (g) + 4H 2 O(g)

How many grams of CaCl 2 can be produced from 65.0 g of Ca(OH) 2 according to the following reaction,

Ca(OH) 2 + 2HCl → CaCl 2 + 2H 2 O

How many moles of oxygen are formed when 75.0 g of Cu(NO 3 ) 2 decomposes according to the following reaction?

2Cu(NO 3 ) 2   → 2CuO + 4NO 2  + O 2

How many grams of MnCl 2  can be prepared from 52.1 grams of MnO 2 ?

MnO 2  + 4HCl → MnCl 2  + Cl 2  + 2H 2 O

Determine the mass of oxygen that is formed when an 18.3-g sample of potassium chlorate is decomposed according to the following equation:

2KClO 3 (s) → 2KCl(s) + 3O 2 (g).

How many grams of H 2 O will be formed when 48.0 grams H 2 are mixed with excess hydrogen gas?

2H 2  + O 2 → 2H 2 O

Consider the chlorination reaction of methane (CH4):

CH 4 (g) + 4Cl 2 (g) → CCl 4 (g) + 4HCl(g)

How many moles of CH 4 were used in the reaction if 51.9 g of CCl4 were obtained?

How many grams of Ba(NO 3 ) 2 can be produced by reacting 16.5 g of HNO 3 with an excess of Ba(OH) 2 ?

Ethanol can be obtained by fermentation – a complex chemical process breaking down glucose to ethanol and carbon dioxide.

                                                  C 6 H 12 O 6    →    2C 2 H 5 OH   +    2CO 2                                                       glucose                   ethanol

How many mL of ethanol (d =0.789 g/mL) can be obtained by this process starting with 286 g of glucose?

36.0 g of butane (C 4 H 10 ) was burned in an excess of oxygen and the resulting carbon dioxide (CO 2 ) was collected in a sealed vessel.

2C 4 H 10 + 13O 2 → 8CO 2 + 10H 2 O

How many grams of LiOH will be necessary to consume all the CO 2 from the first reaction?

2LiOH + CO 2 → Li 2 CO 3 + H 2 O

13. Which statement about limiting reactant is correct?

a) The limiting reactant is the one in a smaller quantity.

b) The limiting reactant is the one in greater quantity.

c) The limiting reactant is the one producing less product.

d) The limiting reactant is the one producing more product.

Find the limiting reactant for each initial amount of reactants.

4NH 3 + 5O 2 → 4NO + 6H 2 O

a) 2 mol of NH 3 and 2 mol of O 2

b) 2 mol of NH 3 and 3 mol of O 2

c) 3 mol of NH 3 and 3 mol of O 2

d) 3 mol of NH 3 and 2 mol of O 2

Note:  This is not a multiple-choice question. Each row represents a separate question where you need to determine the limiting reactant.

How many g of hydrogen are left over in producing ammonia when 14.0 g of nitrogen is reacted with 8.0 g of hydrogen?

N 2 (g) + 3 H 2 (g) → 2 NH 3 (g)

How many grams of PCl 3 will be produced if 130.5 g Cl 2 is reacted with 56.4 g P 4 according to the following equation?

6Cl 2 (g) + P 4 (s) → 4PCl 3 (l)

How many grams of sulfur can be obtained if 12.6 g H 2 S is reacted with 14.6 g SO 2 according to the following equation?

2H 2 S(g) + SO 2 (g) → 3S(s) + 2H 2 O(g)

The following equation represents the combustion of octane, C 8 H 18 , a component of gasoline:

2C 8 H 18 (g) + 25O 2 (g) → 16CO 2 (g) + 18H 2 O(g)

Will 356 g of oxygen be enough for the complete combustion of 954 g of octane?

When 140.0 g of AgNO 3 was added to an aqueous solution of NaCl, 86.0 g of AgCl was collected as a white precipitate. Which salt was the limiting reactant in this reaction? How many grams of NaCl were present in the solution when AgNO 3 was added?

AgNO 3 (aq) + NaCl(aq) → AgCl(s) + NaNO 3 (aq)

Consider the reaction between MnO 2 and HCl:

MnO 2 + 4HCl → MnCl 2 + Cl 2 + 2H 2 O

What is the theoretical yield of MnCl 2 in grams when 165 g of MnO 2 is added to a solution containing 94.2 g of HCl?

Percent Yield

21. In a chemistry experiment, a student obtained 5.68 g of a product. What is the percent yield of the product if the theoretical yield was 7.12 g?

When 38.45 g CCl 4 is reacted with an excess of HF, 21.3 g CCl 2 F 2 is obtained. Calculate the theoretical and percent yields of this reaction.

CCl 4 + 2HF → CCl 2 F 2 + 2HCl

Iron(III) oxide reacts with carbon monoxide according to the equation:

Fe 2 O 3 ( s ) + 3CO( g ) → 2Fe( s ) + 3CO 2 ( g )

What is the percent yield of this reaction if 623 g of iron oxide produces 341 g of iron?

Determine the percent yield of the reaction if 77.0 g of CO 2  are formed from burning 2.00 moles of C 5 H 12  in 4.00 moles of O 2 .

C 5 H 12 + 8 O 2 → 5CO 2  + 6H 2 O

The percent yield for the following reaction was determined to be 84%:

N 2 ( g ) + 2H 2 ( g ) → N 2 H 4 ( l )

How many grams of hydrazine (N 2 H 4 ) can be produced when 38.36 g of nitrogen reacts with 6.68 g of hydrogen?

Silver metal can be prepared by reducing its nitrate, AgNO 3  with copper according to the following equation:

Cu( s ) + 2AgNO 3 ( aq ) → Cu(NO 3 ) 2 ( aq ) + 2Ag( s )

What is the percent yield of the reaction if 71.5 grams of Ag was obtained from 132.5 grams of AgNO 3  ?

Industrially, nitric acid is produced from ammonia by the Ostwald process in a series of reactions:

4NH 3 ( g ) + 5O 2 ( g ) → 4NO( g ) + 6H 2 O( l )

2NO( g ) + O 2 ( g ) → 2NO 2 ( g )

2NO 2 ( g ) + H 2 O( l ) → HNO 3 ( aq ) + HNO 2 ( aq )

Considering that each reaction has an 85% percent yield, how many grams of NH 3 must be used to produce 25.0 kg of HNO 3 by the above procedure?

Aspirin (acetylsalicylic acid) is widely used to treat pain, fever, and inflammation. It is produced from the reaction of salicylic acid with acetic anhydride. The chemical equation for aspirin synthesis is shown below:

In one container, 10.00 kg of salicylic acid is mixed with 10.00 kg of acetic anhydride.

a)  Which reactant is limiting? Which is in excess? b)  What mass of excess reactant is left over? c)  What mass of aspirin is formed assuming 100% yield (Theoretical yield)? d)  What mass of aspirin is formed if the reaction yield is 70.0% ? e)  If the actual yield of aspirin is 11.2 kg, what is the percent yield? f)  How many kg of salicylic acid is needed to produce 20.0 kg of aspirin if the reaction yield is 85.0% ?

3 thoughts on “Stoichiometry Practice Problems”

You forgot the subscript 3 for O in the molecular formula for acetic anhydride and the reaction is not balanced as written. For part F) it’s 18.1 kg and not1.81 kg as written in the final line of the solution.

Thanks for letting me know! Fixed.

You’re welcome!

Leave a Comment Cancel reply

Notify me of followup comments via e-mail. You can also subscribe without commenting.

Resource Topic: Stoichiometry

The mole, molarity, and density, autograded virtual labs, metals density problem, autograded virtual lab.

In this activity, students use the virtual lab to identify 3 unknown metals by measuring their density and comparing their measurements to the densities of known metals. In this randomized version, each student…

Creating a Stock Solution

In this activity, students use the virtual lab to create dilute solutions from a concentrated stock solution of acids or bases. They must first calculate the correct volumes of concentrated acid solution and water…

Scenario-Based Activities

Mixed reception, scenario-based activity.

An in-class activity in which students use molar mass calculations, the scientific method and basic knowledge of chemical reactions to solve a murder mystery. The activity begins with a 5 minute introductory video,…

[ChemVlab+] Powderade: Using Sports Drinks to Explore Concentration and Dilution

In this interactive activity, students first use color to determine which drinks are the most concentrated. Next students use the Virtual Lab to create solutions whose concentration matches that of two characters…

[ChemVlab+] The Factory: Using a City Water System to Explore Dilution

In this interactive activity, students must determine whether the factories in a fictional town are adhering to the guidelines the city has established for their emissions. The challenge is that, for some factories,…

[ChemVlab+] Gravimetric analysis and a closer look at drinking water

In this interactive activity, students first learn how gravimetric analysis can be used to determine the concentration of various species in water, through a combination of particulate-level representations and…

Simulations

Periodic table.

This simulation provides an interactive periodic table that also includes illustration of electron configurations in periodic trends. The schematic diagram to the right of the table plots the electron configurations…

This tutorial introduces the concept of the mole and how it is used in chemistry to connect macroscopic and molecular level scales. Practice is provided on the applied definition of the mole.

Solution Stoichiometry (Molarity)

This tutorial provides a quantitative overview of substances in solution and practice quantifying the amount of a substance in a solution. Guided practice in solution concentration calculations is provided.

Measuring Density

This tutorial explains the definition of density and explains how to perform density measurements. Guided practice in density calculations is also provided.

Calculating Molecular Weight

This tutorial provides instruction and practice on how to calculate the molecular weight of a substance from the atomic weights given on the periodic table.

Composition Stoichiometry

This tutorial provides instruction and practice converting between moles of a molecule and the moles of atoms that the molecule is composed of.

Significant Figures

This tutorial provides a brief review of the guides for determining how many significant figures to include when reporting your answer in a chemistry calculation. Guided practice in performing significant figures…

Dimensional Analysis/Stoichiometric Conversions

This tutorial provides a brief overview of dimensional analysis, including conversion between the amount of a substance expressed in "number of molecules" and the amount of a substance expressed in "moles of molecules".

Using Molecular Weight

This tutorial explains use the molecular weight to convert between the macroscopic scale (grams of a substance) and the microscopic scale (number of molecules of that substance). Guided practice performing molecular…

Making a Standard Solution from Another Solution: Dilution

This tutorial begins with the concept of concentration and expands this to the concept of dilution. It then provides and overview of the calculations and procedure for performing a dilution in the laboratory. Guided…

Virtual Labs

Glucose dilution problem, virtual lab.

In this activity, students use the virtual lab to create a 0.025M glucose solution from a standard 1M glucose solution. First, they calculate the correct volumes of 1M glucose solution and water to mix together…

Acid Dilution Problem

In this activity, students use the virtual lab to create 500mL of 3M HCl solution from a concentrated stock solution of 11.6M HCl. They must first calculate the correct volumes of 11.6M HCl solution and water to…

Cola and Sucrose Concentration Problem

In this activity, students use the virtual lab to prepare a sucrose solution for a soda recipe. They next calculate the concentration of their solution in terms of molarity, percent mass and density. Finally, they…

Making Stock Solutions from Solids

In this activity, students use the virtual lab to create stock solutions starting from solid salts. Students must first calculate the correct amount of solid to make the solution. Next, they prepare the solution…

Identifying the Unknown Metal (Metals Density Problem)

In this activity, students use the virtual lab to identify an unknown metal by measuring its density and comparing their measurements to the densities of known metals.

Identifying an Unknown Liquid from its Density

In this activity students use the virtual lab to design an experiment to determine the identity of mislabeled bottles using the densities of the solutions inside.

Alcohol Density Problem

Determine the concentration of an alcohol solution from its density.

Reaction Stoichiometry and Limiting Reagents

Chemical remediation of arsenic.

In this problem, students determine the limiting reagent in a reaction involving the remediation of arsenic from drinking water.

Determining Reactants and Products in a Solution of DNA

In this limiting reagents problem, students are given random volumes and concentrations of DNA solutions and are asked to predict what will remain after a reaction has occurred. Students can check their prediction…

Determine the Concentration of Unknown Silver Nitrate Solution

In this limiting reagents problem, students are asked to determine the amount of silver nitrate dissolved in a solution by performing a reaction with solid NaCl. In this randomized activity, each student is given…

Determining Stoichiometric Coefficients

Students use the virtual lab to determine how 4 unknown substances react with each other including their stoichiometric coefficients. In this randomized activity, each student receives a different reaction and…

Arsenic in Drinking Water

Set in the context of ground water contamination in Bangladesh, this stoichiometry and analytical chemistry activity examines the issues around identifying wells contaminated with arsenic. (Part of a larger online…

[ChemVlab+] Bioremediation of Oil Spills

Getting bacteria to eat oil is a powerful approach to cleaning up oil spills, and the first step is adding a bioremediation accelerator to form clumps that the bacteria will eat. In this activity, students perform…

Stoichiometry Applet

One of the first numerical problems encountered in introductory chemistry is that of "limiting reagents". This applet serves as a supplement to such calculations, providing imagery that helps students see beyond…

Reaction Stoichiometry

This tutorial introduces the concept of reaction stoichiometry, determining the amount of substance that is consumed or produced by a reaction. The tutorial then explains how to calculate how much of a reactant…

The Stoichiometry of Product Formation and Percent Yield

This tutorial provides on overview in determining the amount of product formed by a reaction. It explains how to perform calculations involving how much product was formed in a chemical reaction and explains theoretical…

Limiting Reagents

This tutorial describes how to determine the amount of each reactant that is consumed and each product that is produced in a given chemical reaction. Guided problems as well as a randomized calculation activity…

Gravimetric Determination of Arsenic

In this activity, students use the virtual lab to determine how 4 unknown substances react with each other including their stoichiometric coefficients.

Stoichiometry and Solution Preparation Problem

In this limiting reagents problem, students mix together solutions in different ratios in an attempt to produce a final solution that contains only 1 product.

Textbook Style Limiting Reagents Problems

Textbook-style practice limiting reagent exercises with that can be used as a way to "predict and check" your answers using the virtual lab.

Textbook Style Limiting Reagents Problem II

In this activity, students practice with experiments involving limiting reagents and the test their knowledge to determine the concentration of an unknown solution.

Predicting DNA Concentration

In this limiting reagents problem, students are given specific concentrations of DNA solutions and are asked to predict what products and reactants will remain after a specific volumes are mixed and reaction has…

Unknown Concentration of DNA Solution Problem

In this advanced limiting reagent problem, students use the virtual lab to determine the concentration of a solution of DNA by reacting it with known amounts of a fluorescent dye which binds to the DNA.

Empirical Formula and Mixtures

Mineral composition.

In this randomized calculation activity, students calculate the empirical formula of a compound given its elemental analysis. Step-by-step support and feedback is provided for students who need additional help.

Composition Determination of a Mixture

In this activity, students calculate the percent composition of a mixture of two arsenic-containing minerals. Step-by-step support and feedback is provided for students who need additional help.

Empirical Formula Introduction

This tutorial defines empirical formula and discusses various ways in which it is used.

Determining the Empirical Formula of a Compund from Its Molecular Formula

This tutorial explains how to calculate an empirical formula when given a molecular formula. Guided practice in performing empirical formula calculations from molecular weight is provided.

Determining the Empirical Formula from an Elemental Analysis

This tutorial explains how to obtain a substance’s the empirical formula from an elemental analysis. It discusses how to compare the empirical formula obtained from an elemental analysis with that from a molecular…

Composition of Mixtures

This tutorial explains the advanced topic of using a chemical reaction, such as burning in oxygen, to determine the relative composition of a mixture. Guided practice in performing calculations that involve a mixture…

Gravimetric Analysis

The ChemCollective site and its contents are licensed under a Creative Commons Attribution 3.0 NonCommercial-NoDerivs License.