Apologia Chemistry: Periodicity or Periodic Trends

We are mopping up general chemistry lessons, one of which is Periodic Trends (Module 8 Molecular Structure): metallic character, nonmetallic character, ionic radius, atomic radius, electron affinity, electronegativity, first ionization energy, density, boiling point, melting point, and valency.  I wrote these and assigned each kid a different one.  The kids may use a variety of materials to represent their assigned trend: toothpicks, straws, color, etc.  They must define the trend and explain the pattern across the main group elements of the periodic table. 

Apologia Chemistry: Atomic Theory Timeline

Time lines
In the Module, Atoms and Molecules (Module 3 in 1st edition) has a section on the development of atomic theory.  I think everyone should learn how to make Time lines.  Here are instructions.  I gave the kids this list of scientists who made contribution to Atomic Theory: My list has Amedeo Avogadro, Neils Bohr, Louis de Broglie, James Chadwick, John Dalton, Werner Heisenberg, Dimitri Mendeleev, Robert Millikan, Hantaro Nagaoka, Ernest Rutherford, Erwin Schrodinger, and JJ Thomson.  The kids have to research their births, deaths, and each individual's contributions' to atomic theory.  (Take a look at the link for time lines at the top.  There is a good copy of a student's timeline.)  I think making a timeline and researching the information is the way to understand the scope of the development of the atomic theory.  You may want to include a discussion about the Greek philosophers Leucippus and Democritus.  After writing the list of scientists, I explain the origin of 'atomos'  and explain their contributions.  We omit the Greeks because it would distort the time line. 

Apologia Chemistry: Sample Stoichiometry Lab Report Andrew's Stoichiometry lab report

                                                              2 Grams Lab

Stoichiometry is the calculation of specific amounts of reactants and products in varying chemical reactions. Precipitates are the solid consequent from a liquid solution.

The ingredients include the following: 50ml of water, 4.21g of zinc sulfate heptahydrate, 2.17g of calcium chloride dihydrate, 2 popsicle sticks, 1 scale (digital), 3 coffee filters, 1 filtration apparatus, 1 graduated cylinder, and 1 pair of safety glasses.

Procedures:
            First, the student gathers all the materials, weighs the zinc sulfate heptahydrate and the calcium chloride dihydrate, and uses the graduated cylinder to measure the water. One uses two coffee filters as weigh boats.  the student mixes the 4.21 grams of zinc sulfate with 25ml of water. The student mixes 25ml of water and Zn SO4 7H2O properly, its appearance changes to that of slightly cloudy water. Next, the student mixes another 25ml of water with the 2.17 grams of calcium chloride dihydrate with a popsicle stick, forming another slightly milky mixture. One combines the two solutions, making a milky white substance. The student goes to the filtration apparatus and, using another filter to drain the liquid, pours the milky white precipitate inside. Then, one uses the filtration device to filter the water out of the liquid, creating a slightly crystalline, powdery substance. The student picks up the precipitate using the filter and leaves it to dry for five days. The student weighs the substance and calculates the margin of error based on how close to two grams the substance weighs. If the substance weighs more than two grams, the student leaves it to dry for one more day, weighing it a second time 24 hours later.

Results:
      The initial results are 4.6 grams of the substance. However, after leaving the consequent to dry for another day, the result of the mixture of zinc sulfate and calcium chloride is a substance weighing 2.5g, making a percent error of 25%.

Discussion: The initial error was formed by the water remaining in the precipitate after the first drying session. The water increased the weight, thus changing the percent error calculated. It is assumed that the precipitate is still damp, as it still weighed more than two grams.

Chemical reaction:
           zinc sulfate heptahydrate + calcium chloride dihydrate ---} calcium sulfate + zinc chloride + 9 water

Apologia Chemistry and Physics: Optical Illusions

Rob and the class are still working on forms of energy and will begin Sound Energy next week.  The kids are also completing a lab report for the solar energy project.  I’m prepping optical illusions and want to share these Layers of Learning (Benham Top),  Optical illusions with templates (one of the links is broken), More templates for CDs, Steve Spangler’s spinning disks, Exploratorium Flipsticks, and Exploratorium’s pinhole potato chip camera or camera obscura.


Optics for Kids has a good introduction to optical illusions, one of the most fun lessons all year! Bend their minds with Physics in a Glass, Hide the Cookie in the Box (This blog post).  Try some of these, too.  I’ll update this post with photos when the kids do this lesson.

Apologia Chemistry: Can you make 2 grams lab recap

Let’s summarize the Can You Make 2 Grams Lab post.  We spent eons finishing.  I gave each kid a different combination of reactants, such as magnesium sulfate hepta hydrate and calcium chloride.  The kids had to write and predict the double replacement reaction for their equation.  Then, they had to predict the precipitate.  Next, the class calculated the molar masses for each reactant and the precipitate.  Then the kids converted two grams of precipitate into moles, applied the ratios according to stoichiometry, and calculated how many grams of each reactant was required.  As they did their calculations, I checked formulas, balancing, molar masses, and moles of precipitate, and finally the respective masses of the two reactants.  Yes, this takes forever!  I had purchased a filtration device from Good Will for $26.75 (with shipping).  It worked!  (Home Science Tools sells a similar vacuum pump.  Amazon sells a filtration set which attaches to this hand pump— about $55 from Amazon.) You can do this lab with a funnel and a bottle.  This process is called gravitational filtration.  It takes forever.  Just add the filtrate and precipitate through a funnel and let the liquid seep through the filter paper—coffee papers are fine.  Allow the precipitate to dry for several days before weighing the sample.  Remember, the theoretical yield is 2 Grams.  Next week, the kids will write and edit their reports.

Update: Today we're writing the lab report.  I emphasize technical writing in the third person, present tense, active voice, and indicative mood.  For the example, "The student adds four grams of magnesium sulfate to a beaker." This process is sloooowwww.

Apologia Young Explorer Chemistry and Physics: Introduction to Physics

The past few weeks the kids have started Physics and experienced loads of interruptions from Christmas break, travel, and the flu.  Here are a few of the skills: Motion, Physics tricks, Horsepower, Static electricity, transfer of energy, potential and kinetic energy, etc.
Here are a few of the resources to try:
1. Rocket Balls
2.Ball Drop (Gravity): Drop balls with different masses (baseball, ping pong, tennis ball, etc.)
3. Horse Power Lab
4. Wind Up Toy
5. Physics toys: rattleback, flipover top, balancing bird
6. Friction Lab (easy) and Friction Lab (We did this one.)
7. Introduction to Newton's Laws Lab Activities
8. Static Labs (We'll do more electrical labs later.  We did static now because it's winter and the air is dry.  These do not work well during the humid spring.)

How do the toys operate? Here are the explanations..rattleback, wind up toy, balancing bird

Apologia Chemistry: Still Working Out Moles or Stoichiometry

We're still working on Stoichiometry.  Really.  My goal is to complete Flinn's Can You Make 2 Grams? lab.  Today, we're doing a lab on solubility and precipitates, similar to this one.  The kids make a data table and record whether or not a precipitate forms.  (See the video below.) ( I brought extra chemicals to Co-op today to allow the kids to make some solutions, too.  I want them to use several skills. Ideally, they would make 1 M solutions. In reality, they mix a little compound with 50 mL of cold tap water.)  After they record their reactions, the next step is to predict patterns to understand solubility rules.  I began by telling them all of the reactants are soluble and exhorted them to react all the chemicals with lead II nitrate and silver nitrate.  Once the kids have teased out solubility rules, they're going to write and balance the double replacement reactions for the combinations which form a precipitate.  The goal is to understand precipitates, solubility rules, and review double replacement reactions--all in preparation for the 2 Grams lab.  Really.

Update: The kids needed more time to collect data, predict and write the double replacement reactions, and tease out the solubility rules from data.  They are writing formulas and balancing equations concurrently.   The process is slow.

Update: Today we spent the class mopping up Beanium, The Mole Lab, Precipitate Lab before finally beginning the 2 Grams Lab on Thursday.

Update: First, here is a copy of the 2 Grams Lab with the balanced equations, molar masses, and grams of reactants.  Today, we completed the lab!!!!!  Next week, we're writing the Lab Report Rubric (Here is an example from former students.)  I even have photos!!!!