Introduction to Stoichiometry

Introduction to Stoichiometry

Author: carolyn fruin

Learning Targets:

  • I can define "stoichiometry."
  • I can use stoichiometry to convert between the following quantities : particles, mass, moles, and volume.
  • I can define "limiting reagent" and be able to identify the limiting reagents in reactions.
  • I can define "excess reagents" and be able to identify excess reagents in chemical reactions.
  • I can calculate the final masses of all reactants/products given the mass of any substance involved in the chemical reaction. 

Stoichiometry may sound complicated, but  in reality, stoichiometry is just math with balanced chemical reactions. Therefore, it is very important to make sure you are always using a BALANCED chemical reaction when working on a stoichiometry problem. There are several different paths and quantities we may calculate using essentially the same system. They could be:

1. Mole to Mole
2. Moles to Grams
3. Grams to Moles
4. Grams to Grams
5. Grams to Liters
6. Molecules to Grams

Below is the flow chart that we will use to solve these problems. Particles are not present simply because to measure these is real life wouldn't happen. The important thing is to know what unit you are starting with in the problem, and what unit your final answer should be in. The arrows between units represent conversion factors. Remember, when entering into a calculator, everything on the top is multiply, everything on the bottom is divide, and you hit enter just once to avoid rounding errors.


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Prelearning Video Chapter 9

View the Chapter 9 Video and complete the guide below to prepare for the course instruction on stoichiometry.

Chapter 9 Video Viewing Guide

Complete the document while viewing the video above.

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PhET Lab Simulation - Molar Ratios

Use the following PhET Simulation to complete the activity attached below to understand mole relationships in chemical reactions.

PhET Lab Simulation Guide - Molar Ratios

Use the simulation above to complete the document.

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Introduction to Stoichiometry (part 1)

This is a nice video on the basics of stoichiometric relationships.

Source: KhanAcademy

Introduction to Stoichiometry (part 2)

Another video with some simple examples on mass to mass relationships.

Source: ChemAssistBeta