Solutions Test Today!

Be sure and schedule a makeup time ASAP – tomorrow or Monday is best so it’s still fresh in your mind!

Tomorrow we start talking about gases. If you want to get a head start, begin looking over Chapter 5!

A few more helpful precipitate prediction sites

Hey – here are a few practice sites for the solubility rules and reaction writing since Mr. Guch doesn’t seem to have any of those.

Quizlet – Flashcard-type practice that asks you to decide if a compound is soluble or not. The instructions aren’t great (in the sense that there aren’t any) – type YES if it is soluble and type NO if it is insoluble (makes ppt).

Reaction practice – it doesn’t come with a key, but I made one! ppt practice key

More solubility practice – A few compounds at the end of this page to determine soluble/insoluble. Warning, the key is literally 2 lines below the questions so if you don’t want to be tipped off, scroll down SLOWLY.

Remember you can always have a friend print their Webassign for you to get some new problems – at this point the key will be showing!

The Mole!

Introduced the concept of the mole, a unit used in chemistry. Like a dozen, it is a word that means a specific number of things. A mole is equal to 6.022 x 10²³ basic particles, such as atoms, molecules, ions, or electrons. So a mole of copper metal contains 6.022 x 10²³ atoms of copper. A mole of water contains 6.022 x 10²³ molecules of water.

The mole is the number of atoms of C-12 that have a mass of exactly 12 grams – the same value for the mass of a single C-12 atom in amu. Since the masses on the periodic table are relative, that means that a mole of an element  weighs, in grams, the atomic mass of that element from the periodic table. This is known as the “molar mass” – the mass of one mole. The mass of a mole of a compound can be found by adding the molar masses of the elements that the compound is made of.

So, a mole of hydrogen atoms weighs 1.008 g. A mole of oxygen atoms weighs 16.00 g. A mole of water, which is comprised of 2 H and one O, would weigh 2(1.008) + 16.00 = 18.02 g.

The molar mass of a covalent (molecular) compound is sometimes referred to as the molecular mass or molecular weight. These terms mean the same thing as molar mass – the mass of one mole of the substance.

Organic Compounds

Last type of naming – organic compounds.

Compounds based on chains of carbons are classified as organic. Usually, the first element in the formula will be carbon, followed by hydrogen and possibly other elements. Compounds containing only carbon and hydrogen are called hydrocarbons and are named using a prefix for the number of carbons in the chain, and a suffix for the type of bonds between the carbons.

Test on Naming Tuesday 11/3!

Polyatomic Ions

Recap of transition metal naming. Introduced polyatomic ions. Just like vocabulary in a foreign language, these need to be memorized. Click on the link below for the table of ions that need to be memorized for this year.

polyatomics

Quiz on Polyatomic Ions Wednesday 10/28!!

Attached to this post is a Powerpoint polyatomic Jeopardy game (I hope)!

Polyatomic Jeopardy

Chromatography Lab, Day 2

Today we took measurements and calculated Rf for our pigments. Lab books were turned back in at the end of class.

Reminder! There is a WebAssign up that’s due next Tuesday! You can do questions 4, 5,  and 8 now based on what we have covered in class so far. The remainder of the assignment will be based on what we discuss over the next few days.

Unit 2 test on Wednesday 10/7!

Welcome to Chemblog!

OK! We are going to give this a shot. This blog will be a source for our daily activities in class, as well as a place for me to put some links to useful websites for practice and more information on various topics. If you miss class, you can come here and find out what you missed. I may put some notes here as well, but that depends on storage room….since I’m doing this for free and don’t want to pay for extra space.