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Unit 3 - Quantifying Chemical Change

The "story" of Chemistry continues as we delve deeper into the periodic table and the topic of chemical change. In Unit 3, we will discuss the more mathematical topics associated with elements, compounds, compounds and chemical reactions. We will add to the conceptual and descriptive knowledge we learned about in Unit 2 by putting numbers to the topic. We will learn about such concepts as average atomic mass, the mole as a counting unit, molar mass, mass-to-mole-to-particle conversions, percent composition, emperical formulas, and the mathematical relationships between the amounts (mass, moles, etc.) of reactants and the amounts of products involved in a chemical reaction.

We will be testing on about the 10th block of the unit. There will be several labs, a small project, and the usual battery of WebAssigns. Bring your calculator every day as you will be using it quite regularly.

Ponderings, Musings, and Other Things

There's always a story in the history of Chemistry. The topic is about more than atoms and molecules, elements and compounds. It is also a story about people and there quest to make sense of and understand the world of chemistry. And if you're interested in a little history about Avogadro's number, check out the following blog post from WIRED magazine.

Even Avogadro Didn't Know Avogadro's Number

Keep Up

Don't fall behind in chemistry at this point. The snowball effect will occur.

That is, you will feel like you're running down a snowy hill with a rolling snowball rolling behind you. The further you go, the bigger the snowball becomes until finally ... .

Hopefully, you get my drift.

Come in and get some help when you need it. Use the referenced web pages and YouTube videso as well. (I highly recommend Tyler DeWitt's YouTube channel.)

Bring a Calculator Everyday

There won't be a day that goes by for the rest of the unit (and possibly the course) in which we don't use a calculator. Bring a calculator everyday.

Quiz Key:

The key to Wednesday's Names and Formulas Quiz is available online. View Quiz Key.

We are done with names and formulas. We will be using these skills all year. Having troubles? Seek help. I'm available all lunch periods.


There are three WebAssigns due on Tuesday, October 14. There is a reading WebAssign, a Reaction Type WebAssign, and a longer Reaction Type WebAssign. The longer Reaction Type WebAssign is optional (it says so ... but you're going to have to read). If you do this OPTIONAL WebAssign there you will be given a fifth throwout. If you don't do this WebAssign, then it will be an automatic throwout. It's your choice.

The End is Near!

The End is NearUnit 2 will end on Thursday, October 18. We will complete coverage of Unit 2 concepts on Friday, October 12. Coverage of Unit 3 begins on Tuesday, October 16. This provides you with several days to go through the Unit 2 content, freshen up on names, formulas, reaction types, precipitation reactions and equation balancing. And finally, it gives you plenty of time to worry about the Unit 2 test ... so pace yourself.

There are several good ways to review for your Unit Test. These include going over your Unit 2 Packet, reviewing the textbook readings, going over Past Due WebAssigns, and doing the optional Unit 2 Review WebAssign.

About the Unit 2 Test

The Unit 2 Test will have approximately 17 Multiple Choice questions covering basic conceptual comprehension (34 pts). There are 2 questions with 6 parts each that involve names and formulas (24 pts). There are 8 questions in which you must read about a reaction description and write a balanced chemical equation; the best 7 scores will be counted (28 pts). Finally, there are two questions in which you must write a molecular equation and a net ionic equation for a precipitation reaction (16 pts). That totals to 102 pts; we will just make 100 pts a perfect score.

Good To Know News

Every nine weeks, students are allowed to throw out three WebAssigns. The grade will be entered into the grade book as is and the corrections will be made at the end of the second unit. At that time, the three "most damaging" WebAssign grades are excused.

During the first quarter, there was a special offer: The "Ions" WebAssign was optional. It served the effect of being a fourth WebAssign throw-out. Unlike the other WebAssigns, a 0 on this WebAssign will be entered into the gradebook as an EX and remain as an EX.

Get to Know the Table

It's perhaps the greatest and most popular infographic of all time! It's called the Periodic Table and it falls within the realm of science. No - you don't need to "memorize the periodic table." But you do need to become familiar with it. And besides, what educated individual wouldn't want to know a bit about the greatest infographic of all time!

There's numerous Periodic Tables across the web. Here's one of your teacher's favorites - the Dynamic Periodic Table. Interact with it and start of learn. Curious minds need to know ... the periodic table.

The Dynamic Periodic Table

Periodic Table - Terrific Triva

Origins of Elements NamesWe will be learning much about the Periodic Table of elements over the next few weeks. One of the most interesting sources of information is the Compound Interest website. It is definitely worth checking out ... and I don't get any $$ for saying so. At this point, you might be interested in finding out where all the names of elements come from? Click the link (or image) and find out:

The Periodic Table - Origin of Elements' Names

More About WebAssigns

There will be two types of WebAssigns: Reading Guides and Practice Assignments. They are set up quite differently. Reading Guides will allow one attempt per question; you will not reeceive feedback until after the due date. They will be discussed after completion. They are graded very leniently; that is, your grade on the assignment will be much better than your grade on the WebAssign; think of them as being abnormally curved. NEVER worry about what your grade is on a Reading Guide; leave that worry up to me. Practice Assignments are the second type of WebAssign. You are more accustomed to this type from Physics. You receive immediate feedback. You are allowed multiple attempts. And your grade on the WebAssign is (for the most part) your grade on the assignment.

    Online Homework


This page changes nearly every day; re-load or refresh to receive the most recent schedule.

Today in Class

>> Thursday, October 18 <<

Focus Question(s):
  • What did we learn in Unit 2?
  • How can molar mass and Avogadro's number be used as conversion factors to relate mass, moles, and number of particles?

  • Continue Unit 3 Activities (~35 minutes):
    Discuss Chapter 8.1-3 Reading Guide (Packet, pp. 3-4)
    The Mole and Atomic Mass (p. 6)
    Molar Mass of Compounds (p. 9)
    Mole Conversions (Selected Qs from pp. 11-12)

  • Test on Unit 2 (~50 minutes)



Next Time in Class

>> Monday, October 22 <<

We will continue our discussion of the use of molar mass and Avogadro's number to do mole conversion problems. We will discuss the Chapter 8.5-6 Reading Guide. BUT the highlight of the lesson will be Lab QCC3. We will roast Mg at high temperatures to synthesize MgO and determine the emperical formula of the product.

Periodic Tables

Are you in need of a periodic table?  Try one of the following websites:

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