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How to do Stoichiometry Problems (16 Favorites)

LESSON PLAN in Stoichiometry, Mole Concept, Dimensional Analysis. Last updated October 14, 2019.


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 mole-mole, mole-mass, and mass-mass 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 1023 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



Moles given



x


Mole Ratio
(Balanced Equation)

moles of unknown
moles of given



x



(Conversion)

P.T. mass unknown
1 mole of unknown


=

Mass to Moles


Mass given


x


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


x

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.

  1. Calculate the number of moles of nitrogen dioxide (NO2) produced when 3.0 moles of oxygen are produced in the decomposition of nitric acid by light? (12 mol NO2)
  2. 4 HNO3 → 4 NO2 + 2 H2O + O2

  1. Calculate the number of moles of Na2CS3 produced from 0.60 moles of CS2 by the following reaction. (0.40 mol Na2CS3)

3 CS2 + 6 NaOH → 2 Na2CS3 + Na2CO3 + 3 H2O

  1. How many grams of Si3N4 can be produced from 0.46 moles of N2? (32 g Si3N4)

3 Si + 2 N2 → Si3N4

  1. How many moles of NO can be produced from 0.680 g of NH3 according to the following reaction? (.0399 mol NO)

4 NH3 + 5 O2 → 4 NO + 6 H2O

  1. How many moles of SO2 are required to convert 6.8 g of H2S according to the following reaction? (0.10 g SO2)

2 H2S + SO2 → 3 S + 2 H2O

  1. How many grams of carbon is required to produce 9.460 grams of SiC? (8.500 g C)

SiO2 + 3 C → SiC + 2 CO

  1. How many grams of HClO3 can be produced from 7.2 g of ClO2 according to the following reaction? (7.5 g HClO3)

6 ClO2 + 3 H2O → 5 HClO3 + HCl

  1. How many molecules of H2O2 are required to react with 11.0 g of N2H4 according to the following reaction? (1.45 x 1024 H2O2)

7 H2O2 + N2H4 → 2 HNO3 + 8 H2O