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How to do Stoichiometry Problems (16 Favorites)
LESSON PLAN in Stoichiometry. Last updated December 20, 2018.
Summary
In this lesson, students learn templates for performing stoichiometry problems. They then put the methods to the test with a practice worksheet.
Grade Level
High school
Objectives
By the end of this lesson, students should be able to
 perform molemole, molemass, and massmass stoichiometry problems.
Chemistry Topics
This lesson supports students’ understanding of
 Stoichiometry
Time
Teacher Preparation: 30 minutes
Lesson: one class period
Materials
 Student handout
Safety
There are no special safety considerations for this activity.
Teacher Notes
 In this lesson, students receive a handout with templates that outline how to perform different types of stoichiometry problems.
 Work through examples of each with the students before giving them problems to work through on their own.
 Included is a practice worksheet for students. The final answer is provided on the worksheet so students can verify their answers, but the answer key shows the work required to arrive at the final answer.
For the Student
Stoichiometry Notes
Conversions:
 1 mole = mass on periodic table (P.T.)
 1 mole = 6.022 x 10^{23} particles (Avogadro’s number)
 1 mole = 22.4 L of a gas at STP (standard temperature and pressure)
(One example of each step problems)
A balanced equation is necessary for the mole ratio!
2 Step Example Mole to Mole 
Moles given 
x 
(Balanced Equation) moles of unknown moles of given 
= 

3 Step Examples Mole to Mass 


Mole Ratio (Balanced Equation) moles of unknown moles of given 

(Conversion) P.T. mass unknown 1 mole of unknown 

Mass to Moles 


(Conversion) 1 mole of unknown P.T. mass given 

Mole Ratio (Balanced Equation) moles of unknown moles of given 
= 
4 step Example Mass to Mass Mass given 

x 
(Conversion) 1 mole of given P.T. mass given 
x 
Mole Ratio (Balanced Equation) moles of unknown moles of given 
x 
(Conversion) P.T. mass unknown 1 mole of unknown 
= 
Stoichiometry Practice (Worksheet)
Using the tips you just learned about to solve a stoichiometry problem, answer each of these problems. Show all work and consider significant figures. The final answer is provided for you in (bold) so you can immediately check to know whether you solved the problem correctly. If you didn’t arrive at the correct answer, try the problem again. You will need a periodic table to complete this activity.
 Calculate the number of moles of nitrogen dioxide (NO_{2}) produced when 3.0 moles of oxygen are produced in the decomposition of nitric acid by light? (12 mol NO_{2})
4 HNO_{3} → 4 NO_{2} + 2 H_{2}O + O_{2 }
 Calculate the number of moles of Na_{2}CS_{3} produced from 0.60 moles of CS_{2} by the following reaction. (0.40 mol Na_{2}CS_{3})
3 CS_{2} + 6 NaOH → 2 Na_{2}CS_{3} + Na_{2}CO_{3} + 3 H_{2}O
 How many grams of Si_{3}N_{4} can be produced from 0.46 moles of N_{2}? (32 g Si_{3}N_{4})
3 Si + 2 N_{2} → Si_{3}N_{4}
 How many moles of NO can be produced from 0.680 g of NH_{3} according to the following reaction? (.0399 mol NO)
4 NH_{3} + 5 O_{2} → 4 NO + 6 H_{2}O
 How many moles of SO_{2} are required to convert 6.8 g of H_{2}S according to the following reaction? (0.10 g SO_{2})
2 H_{2}S + SO_{2} → 3 S + 2 H_{2}O
 How many grams of carbon is required to produce 9.460 grams of SiC? (8.500 g C)
SiO_{2} + 3 C → SiC + 2 CO
 How many grams of HClO_{3} can be produced from 7.2 g of ClO_{2} according to the following reaction? (7.5 g HClO_{3})
6 ClO_{2} + 3 H_{2}O → 5 HClO_{3} + HCl
 How many molecules of H_{2}O_{2} are required to react with 11.0 g of N_{2}H_{4} according to the following reaction? (1.45 x 10^{24} H_{2}O_{2})
7 H_{2}O_{2} + N_{2}H_{4} → 2 HNO_{3} + 8 H_{2}O