Tuesday 9.14.10

Today, our class was shortened by 10 minutes because of the Fall Sports Assembly. We learned about a new topic, atoms, and were given four worksheets to tape in our composition notebook. We learned several new terms which relate to atoms, and were crucial in helping us do the problems on the worksheets. The terms are the following:

Atom: Most basic unit of matter (example: one atom of zinc)

Molecule: Group of atoms held together by a chemical bond

Element: Made up of a single type of atom (example: two atoms of zinc)

Compound: Molecule made up of more than one type of atom. If something is a compound, it is always a molecule.

Pure Substance: Made up of one type only

Mixture: Mixture of two types

It wasn't specified what these "types" are.

On the worksheets, we did numbers #1-9. Number 1 was defining the above terms. For number 2, we were given atomic level diagrams, and we were told to identify each as being either an element or a compound, and consisting of either atoms or molecules. For number 3, we had to answer the question: Can a substance that is a compound ever be made of individual atoms and not molecules? Explain. The answer was No, because compounds are always made up of molecules. For number 4, we had to answer the question: Can a substance that is an element ever be made of molecules and not individuals atoms? Explain. The answer was Yes, because an element can have two of the same atoms connected together.

For numbers 6 and 7, we were given a key to use. The key was three circles which were shaded differently. An unshaded circle was H, a striped circle was O and a shaded circle was C. For number 6, we had to write the formula for each of the following atomic level pictures. We learned that if two of the same atoms were bonded together, then the "2" was subscripted , not written in front of the letter. For example, two chemically bonded Hs would be "H₂" , while two separate H atoms would be "2H".

For number 7, we were given the following formulas, and we had to draw a picture to match them. We used the same key that we used for number 6. For number 8, we were given pictures, and we had to write the formula and a description to match the picture. It's the opposite of what we had to do in number 7, but we also had to write a description. The description is basically a list of terms that appeared in the picture. The terms that we could use were atom, molecule, element, compound, pure substance and mixture.


The last page has numbers 9 through 13, but we were only told to go up to number 9. In number 6, we were given a formula, and had to draw a matching picture. In number 7, we were given a sample, and had to write the formula and description. Now, in number 9, we're given a formula, and have to draw a matching picture and description.
Homework: 5 webassigns due Monday the 20th.
You can get to the Webassigns by logging on to Moodle, clicking on Chemistry class, and clicking on "Webassigns, or you can go to webassign.net. To log in, your username is your ID number, the institution is glenbrooksouth.il, and your password is your ID number.