Monday, October 11, 2010

We walked into class today and were automatically instructed to pick up our graded composition lab notebooks already waiting on the back lab benches. After the class returned to their desks, Mr. Henderson put up the seat chart and asked for volunteers to contribute to our blog. Following the blogging business, Mr. H quickly reminded us of the "pop" quiz we had today and told us to take out our unit 2 packets and turn to page 10.

Once on page 10, Mr. H proceeded to remind us about the difference between ionic and molecular (covalent) bonds (compounds).

• ionic (eye-ohn-ik): compounds between cations (metals) and anions (non-metals)
• molecular (muhl-ehk-yoo-lur): compounds between only anions

We then started to complete page 10. Part one was identified as ionic compounds and we therefore knew we were dealing with metals. The answers are as followed:

a) Magnessium iodide

b) Sodium sulfide

c) Calcium bromide

d) (Typo possibly?)

Next, we identified part two as ionic compounds with multi-valent cations (transitional metals). The answers are as followed:

a) Copper(II) chloride

b) Cobalt(II) sulfide

c) Manganese(III) chloride

d) Copper(I) sulfide

For polyatomic ions (part 3), we only went over b. The answer is Ammonium sulfide.

For part 4, the reverse was to be done. The answer to e was (NH4)2S and to f was (NH4)3PO4.

Mr. H then reminded us the "training wheels" when formulating compounds. He told us to first identify the charges of the ions and the properties of balancing charges and then begin to put together the formula.

Subsequently, we were re-taught how to put together the formulas of molecular compounds. Greek prefixes must be used to indicate the number of atoms of each element in the compound. The only exception to this rule is cases in which there is only one atom of the first element. Further practice can be found on page 11 in the packet.

Our review ended with a quick lesson on putting together the formulas of acids. They generally have the chemical formula HX where X is the nonmetal. Their names take the form of hydro(anion root)ic acid.

( i.e. hydrochloric acid - HCl)

The general formula of an acid and how to create it can be found in Daria's blog before me although remember:

-ate --> -ic

-ite --> -ous

Before passing out our quizzes, Mr. H showed us a brief video on experimenting with the reactions between water and alkali metals. The video can be accessed here:

http://www.youtube.com/watch?v=eCk0lYB_8c0

After this, Mr. H handed out Periodic tables and our pop quizzes and....

THE END!

Y