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Unit 7: Acids, Bases, and Solutions

Unit 7 of our 9-unit course focuses on the topics of Acids, Bases and Solutions. We will discuss such concepts as solution formation, solubility, concentration, molarity, solution stoichiometry, the properties of acids and bases, acid-base neutralization, and acid-base titration. This short 7-day unit will provide the foundation for understand the chemistry of acid and base solutions. There will be several labs - most of which are analytical titration labs. The concepts and mathematics associated with titrations will form the basis of the Semester 2 Maker Project - an Arduino-controlled robotic titrator.

Formation of Solutions

The formation of an aqueous solution can be thought of as occuring in three steps:
  1. Breaking solute particles apart (endothermic step).
  2. Breaking solvent molecules apart (endothermic step).
  3. Surrounding solute particles by solvent particles (exothermic step)

The third step of the process is the exothermic, stabilizing step. It is often referred to as hydration and involves the surrounding of the solute particles by polar water molecules.

View Hydration

WebAssign Grades

WebAssign grades have been entered for Unit 6. Within the next week or two, I will go through the gredes and throwout your four lowest WebAssign grades. For some students, this can amount to a 1-2% increase in your overall grade.

Our fourth quarter of WebAssign assignments has begun. It will include Units 7 and 8 and a fragment of Unit 9. You will receive three new free throw-outs. A fourth can be earned through an optional WebAssign. That WebAssign comes up quite early - like near the end of this week (the week of 3/18). #JustSoYouKnow

Viewing Your Tests

Your Unit 7 tests have been graded, Beginning on Wednesday (3/21), you are welcome to come in during lunch hours or after school to view the tests. Just let me know you're coming and I will have the test ready for you.

What is Meant by "Annotating" in a Lab Report

We tend to do two types of labs - (1) labs that include multiple observations in an effort to identify properties and trends in those properties and (2) labs that include careful measurements and subsequent calculations in an effort to determine an unknown quantitative value. When doing the second of these two types of labs, there are several measurements followed by an extensive set of calculations. The Conclusion section is generally short but the Calculation section is long. The role of the Calculations is to document and present the logic as to how the measurements lead to the quantitative value that the lab proposes to find. A good presentation of measured data and calculations will include annotations. Annotations are short notes that convey what the subsequent calculation involves and the logic behind it. The concept of an annotation was discussed in class on Tuesday, December 6. For those who would like to review the discussion, the notes are provided here.

View Notes on Annotations.

Periodic Table in Pictures and Words

For those who are connoisseurs of periodic tables or simply would like to relish a great moment of geekery, tap the link below and explore on this interactive periodic table of the elements.

Visit Interactive Periodic Table with Words and Pictures.

Mr. H's Little Secret

Pssss.  Hey bud! I have a secret to share. Now that you know how to calculate the molar mass, here's a little cheat you should be permitted to use. It's called a Molar Mass Calculator and you will find several by following the links below. You type in the formula and it calculates the molar mass.

WebQC Chemical Portal (one of my favorites)

EndMemo (allows formula or name entry)

Environmental Chemistry (scroll to bottom)

Molecular Weight Calculator by Lenntech

or Google, e.g. molar mass Al2(SO4)3

    Online Homework


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Today in Class

>> Thursday, March 21 <<

Focus Question(s):
  • How do we quantitatively describe the concentration of a solution?
  • What is dilution and how does one predict the molarity of a diluted solution?

  • Discuss Concentration
    == Chapter 15.2-5 Rdg Guide  (pp. 7-8)
    == Concentration (pp. 11-12 as Twosomes)
    == Concentration (pp. 13-14)
  • Complete Lab ABS2 - Solubility Curve
  • Solution Stoichiometry (pp. 19-20, Q#1, 2)
  • Lab ABS4 - Acid-Base Properties

  • WebAssign: Chapter 15.6-7 Reading Guide (due 4/2)
  • WebAssign: Chapter 15.2-5 Concentration (due 4/4)

Next Time in Class

>> Tuesday, April 2 <<

We will finalize our discussion of Concentration (pp. 11-12) and Dilution (pp. 13-14) and talk more about Solution Stoichiometry (pp. 19-20). We will do Lab ABS4 Acid-Base Neutralization.


Periodic Tables

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

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