Many of my students enter into this unit lacking the necessary math skills needed to successfully understand the mole. So to start the unit I teach students how to do basic unit conversions before introducing the mole as a counting unit. Day 3 of Chemistry Math Boot Camp quizzes students on their understanding of scientific notation and dimensional analysis (factor label). The mole can be a difficult concept for many students, so comprehension of necessary math conversions first makes the transition to the mole easier. I typically spend several days letting students work on factor labeling and scientific notation before introducing the mole.
Performance Expectation (PE)/Disciplinary Core Idea (DCI)
This lesson is not directly aligned with HS-PS1-7, the uses of mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction; and DCI-PS1.B, the fact that atoms are conserved, together with knowledge of the chemical properties of the elements involved, can be used to describe and predict chemical reactions. However, students will need to perform mathematical computations to understand HS-PS1-7 which will require student to have a basic understanding of scientific notation, unit conversions and factor labeling (or proportions).
Science and Engineering Practices (SP)
HS-PS1-7 is one of the few high school Performance Expectations with the primary focuses on the use of mathematics to explain a concept. Mathematical and computational thinking at the 9–12 level builds on K–8 and progresses using algebraic thinking and analysis. Using computational thinking, students will convert from one unit to another, helping them develop the skills necessary to understanding the mole as counting unit for the atom.
Crosscutting Concept (CCC)
This lesson is not aligned with any Crosscutting concept.
This is a short period which runs 42 minutes, instead of the normal 50 minutes. These shortened periods make for good quiz and review days.
To start the period I tell students that they will need a calculator and pencil, and that we will be taking a quiz on dimensional analysis and scientific notation. For the next five minutes I give a review of the past two days and go over a dimensional analysis problem and two scientific notation problems. I find that providing a short review before quizzes and test refreshes students on concepts, relieves assessment stress and improves scores.
After reviewing, I tell students that they need to put correct units on problems and there will be several problems that require dimensional analysis and answers in scientific notation.
After the review I hand out the Quiz. Students have the duration of the period to complete the quiz; however, most students need only 15-20 minutes to complete the quiz. After everyone has the quiz I instruct them (again) to make sure that units are added on to each problem that requires them. I give a brief review of the quiz before letting them start the quiz. Doing a review benefits most students -- as mentioned in the Screencast of student work -- by reminding students of what needs to be completed in each section. After completing the quiz students will start a book assignment that introduces the mole.
Below is what I highlight for students about each section of the quiz.
Scientific Notation Problems
Combined problems (1-3)
After completing the quiz students will start a book assignment that introduces the mole.
As a whole students do very well on this quiz (Quiz 6.1 key), in addition I offer quiz corrections the following day. I do this to make sure that students are realize where they made mistakes and it minimizes issues later when we get to stoichiometry by making students accountable for the information.
On quiz days I like to have an assignment for students to do that is an introduction to the next topic. This can be a difficult task when there are very little resources that aligned with the NGSS. Fortunately, most textbooks have a chapter devoted to the mole. This is one of the few unit that allows me to introduce a topic using the textbook, so I take full advantage of incorporating a literacy component into a lesson. The textbook that I use for this assignment is Modern Chemistry by Holt 2002 edition, pages 80-85. Any textbook will do, however most textbooks (including Modern Chemistry) are not currently aligned with the NGSS. I don’t find this to be an issue in this case, due the fact it’s an introduction and the mole is a standard chemistry concept. This assignment is very easy for students and is completed with no difficulty since it is only introduction to the mole. I find that an assignment such as this provides a good introduction so they can become familiar with the terminology and a basic understanding of the concept.
An alternative to this assignment would be VisionLearning, The Mole: Its History and Use . It's an online resource that introduces the mole and provides a summary quiz that can be completed online and printed. I like to introduce students to a concept using inquiry, but the mole is such a difficult concept for high school level chemistry I find that a brief amount of background knowledge helps in the inquiry process.
Students will have the duration of the period to complete textbook assignment. 6.1, including the following day, so it does not need to be completed for homework. The following class period students will be able to complete the reading assignment, take a make-up quiz and do quiz corrections. The next lesson will be an inquiry activity that demonstrates the concept of a counting unit to determine mass; an inquiry-based lesson before working with the mole.