S - Stoichiometric Calculations (Lesson)
Stoichiometric Calculations
Introduction
You may ask, “Why do we need to measure the ratio of substances in chemical reactions?” What happens when your mom adds too much salt to your favorite cake recipe? Do you eat it? No! Similarly, without a proper study of Stoichiometry, we can’t know the specific quantity of elements that are perfect for the reaction to take place efficiently. In this chapter, we will understand all about the concept of Stoichiometry and look at how we can make stoichiometric calculations. Going forward, this graphic may be helpful when setting up Stoichiometric calculations. We completed mole/particle conversions in the previous module. As you can see, this chart indicates helpful conversion factors that can be used to convert units.
Stoichiometric Calculations
This segment of Chemistry Matters, produced by GPB, explores stoichiometric calculations and mole ratios.
Download the note taking guide for Chemistry Matters Unit 6 Segment D. Links to an external site.
Mole to Mole Conversion Practice
A Closer Look at Mole to Mole Conversion
Let's take a closer look at the Mole to Mole Conversions.
It is very common for students to look at stoichiometry problems with the solution and think to themselves, "Yeah, I understand that. You set it up so that the units cancel. It makes perfect sense." At this point, the student moves to the next problem. When this student sees the same type of problem on a quiz or test, they are lost. Sure, it made perfect sense when they looked at the solution, but without actually trying to solve the problem themselves, nothing was learned. Do NOT look at the solution to these problems immediately. Actually try with a pencil, paper, calculator, and periodic table to solve these problems yourself. After you have tried, then look at the solution. Find your error(s). Learn from what you did wrong.
Mole/Mole Practice Activity One
Mole/Mole Practice Problems
Let’s add one additional step to these problems by converting between mass and moles. You will use the molar mass in addition to the mole ratios to complete these conversions.
The following images outline the basic process of canceling units and introducing new units in these types of calculations. It is very important to UNDERSTAND the process of utilizing conversion factors to solve these stoichiometric problems. DO NOT attempt to memorize these steps. Instead use the units to your advantage.
Mole/Mass Practice Problems
Could you use more practice with mole-mole and mole-mass conversions?
Download the following handouts and corresponding answer keys.
Download the Mole/Mole and Mole/Mass Practice Handout. Links to an external site.
Download the Mole/Mole and Mole/Mass Practice Handout Key. Links to an external site.
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