Wholly GuacaMOLE!!!

Today, we began by getting back our tests from last week. After going through some of our mistakes and questions, Mr. Lieberman suggested that if you still have troubles with naming compounds, you should practice some more problems. Then, we moved on to notes about the mole.
The mole is a counting unit that means 602 billion trillion (similar to a dozen, which is 12) or 602,000,000,000,000,000,000,000, or in scientific notation 6.02x10^23. It is also known as Avogadro's number in honor of Avogadro. A mole is really large in terms of things that we can see, such as soft drink cans, as Avogadro's number of these can cover the surface of the earth to a depth of 200 miles.
The mole is used in the same way a dozen is used:

• 1 dozen cookies=12 cookies
• 1 mole of cookies=6.02x10^23
• 1 dozen cars=12 cars
• 1 mole of cars=6.02x10^23

*The number is always the same, but the mass is different* (Mole is abbreviated mol.)

Moles of particles:

• 1 mole of carbon = 6.02x10^23 C atoms
• 1 mole of H2O = 6.02x10^23 H2O molecules (2 moles of hydrogen and one mole of oxygen)
• 1 mole of NaCl = 6.02x10^23 NaCl "molecules" (6.02x10^23 Na^+ ions and 6.02x10^23 Cl^- ions)

Molar Mass: the mass of 1 mole (in grams) is equal to the numberical value of the average atomic mass (from the periodic table)

• 1 mole of C atoms = 12.0 g
• 1 mole of Mg atoms = 24.3 g
• 1 mole of Cu atoms = 63.5 g

To find the molar mass of molecules and compounds, you add the molar masses together:

1 mole of CaCl2 = (1 mole of Ca x 40.1 g/mol) + (2 moles of Cl x 35.5 g/mol) = 111.1 g/mol CaCl2

Here are some notes for calculations with moles:

• For grams to moles, divide by molar mass
• For moles to grams, multiply by molar mass
• For particles to moles, divide by Avagadro's number
• For moles to particles, multiply by Avagadro's number

The artificial sweetener aspartame has the formula C14H18N2O5. To find out how many moles of aspartame are in 225g of aspartame: 225g of C14H18N2O5 x (1 mol/294 g/mol) = .765 moles of aspartame. (the 294 is from C14 (14x2) + H18 (18x1) +N2 (2x14) + O5 (5x16) = 294 g/mol)

Sorry about the bad formatting. I still couldn't insert the exponents and other such things. For more information about the mole, visit http://www.visionlearning.com/library/module_viewer.php?mid=53 and for more information about Avogadro, visit http://chemistry.about.com/od/famouschemists/a/avogadro.htm.

Don't forget about the worksheet from last week as well as the one from today. Also, there is a quiz on Wednesday!

~Kaitlyn Y.

The next scribe is Alex K.