Monday, November 2, 2009

Moles - the Beginning

Today, students started the day with a small review about coefficients, subscripts, and how to count atoms. We covered some of the material that was on the last benchmark and answered some questions and had a small discussion about test taking skills.

Then we started talking about moles. Moles are used to count atoms. There are 22,000,000,000,000,000,000 quintillion atoms in a grain of sand and even counting grains of sand is a pain. Because atoms are so tiny, we use the mole to estimate.

There are 6.02 x 10 ^23 molecules in one mole. That's a whole lot. This is our new favorite number because it needs to be memorized. We practiced converting from moles to molecules.

Next we discussed molar mass. Molar mass = 1 mole and it also equals atomic mass from the periodic table. To find the molar mass of carbon dioxide you find the mass of carbon and two oxygens and add them together. Finding molar mass is not difficult unless the molecule has tricky subscripts (which we have been practicing).

Homework tonight includes identifying parts of a reaction (unit 4 stuff) and finding molar masses unit 5 stuff).

Tomorrow is Election Day for Element for President! We will see which element campaigns the best!

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