Module 6 Intro

Module 6—Stoichiometry

Lesson 2—Gravimetric Stoichiometry

Get Focused

In Lesson 1 you learned that stoichiometry is a method to predict the quantities of reactants or products involved in a chemical reaction. Whether you plan to launch a rocket, and need to calculate oxygen to fuel ratios, or need to calculate the quantity of product that will result from a chemical reaction, a knowledge of stoichiometry is essential. In Lesson 1 you concentrated on the significance of ratios among the coefficients of different substances in the reaction to this method of calculation.

There are two major drawbacks to the predictions you have made thus far. First, you have only been able to consider chemical quantities of each substance (number of moles) involved. You already know that the number of moles is not a directly measurable quantity. Second, as is the case with all predictions, they need to be confirmed.

In this lesson you will continue your study of stoichiometry by learning how to use the masses of the substances involved in your predictions. You will also perform an experiment to test predictions made using stoichiometry. By completing these activities, you will perform a gravimetric analysis. Gravimetric analyses involve the determination of masses of substances. Open the following sound file to hear how this word is pronounced.

Essential Questions

• How are predictions made about the masses of reactants and/or products involved in chemical reactions?
  
  

• How can you test the predictions made using the stoichiometric method?
  
  

• What is percent yield and how can it be determined?

Module 6: Lesson 2 Assignment

Save Module 6: Lesson 2 Assignment to your course folder. You will receive more information about how to complete this assignment later in this lesson.

You will also continue to work on the Module Assessment (Part 2)—Stoichiometry Calculator. You will submit the work you complete in this lesson to your teacher for feedback, and you will have the opportunity to revise and add to it in other lessons. Remember to keep a copy of your Stoichiometry Calculator in your course folder so you can revise it as you work through this module.

You must decide what to do with the questions that are not marked by the teacher.

Remember that these questions provide you with the practice and feedback that you need to successfully complete this course. You should respond to all the questions and place those answers in your course folder.