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# The Mole

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S: The Mole

FC: The Mole

1: The Mole Lindsey Freund and Spencer Wilson ED416B

2: In chemistry, the mole is the SI unit that describes the amount of a substance.

3: S | Or, if you think like a lawyer, you might prefer the official SI definition: The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilograms of carbon 12. !

4: Owing to their tiny size, atoms and molecules cannot be counted by direct observation. There are, however, a number of indirect methods that enable us to estimate the number of these particles in a sample of an element or compound.

5: Did you know that Avogadro was not the person who actually calculated the famous "Avogadro's number? Robert Brown is credited for the making the measurement in 1827 | Avogadro’s Number ~One mol of anything is just Avogadro's number of that something.

6: How large is a mole?... Let's think of things we see every day! | oA mole of hockey pucks would be equal to the mass of the Moon. | Assuming that each human being has 60 trillion body cells and the Earth's population is 6 billion, the total number of living human body cells on the Earth at the present time is a little over half of a mole.

7: A mole of marshmallows would cover the planet Earth 12 miles high. | A mole of seconds would last so long; the universe would die out before it was done! | A mole of marbles would fill the entire Grand Canyon and there would still be enough left over to displace all the water in Lake Michigan and a few other lakes!

8: Depending on the density of the substance, the mass of that amount of the substance could vary widely. | One mole of hydrogen, for example, would have a different mass than one mole of lead.

9: The question compares two different measurements of a given substance, rather like asking "how heavy is a gallon?" The question becomes "A gallon of what"? | ?

10: When converting from grams to moles or moles to grams you must first find the molar mass of the element or compound. | Converting | The unit of the molar mass will be in grams per moles (g/mole)

11: If the chemical is an element, just read off the atomic mass from the periodic table.

12: If it is a compound, you must know the molecular formula, and then you find the total molar mass of the compound by adding up the atomic masses of each atom in the compound | Molecular Formula: H2O | Example | Molar masses of individual elements: H= 1.008 g/mole O=15.999 g/mole

13: 1.)Multiply the molar mass of the element by the number of atoms of the element that are present in the molecular formula. | Do this for all elements present in the formula | H: 1.008 g/mole x 2 = 2.016 g H/mole H2O O: 15.999 g/mole x 1 = 15.999 g O/mole H2O | 2.)To find the molar mass (the mass of the compound) add together the total mass of each element present in the compound. | 2.016 g/mole H + 15.999 g/mole O = 18.015 g/mole H2O

14: Converting | Once you have the molar mass or formula weight, you can easily convert from grams to moles, and also from moles to grams.

16: References: Tillery, Bill W. Physical Science. 8th ed. New York City: McGraw-Hill Science/Engineering/Math, 2008. Print. Hewitt, Paul G., John Suchocki, and Leslie A. Hewitt. Conceptual Physical Science: Explorations. San Francisco, Calif. ; London: Pearson/Addison Wesley, 2003. Print. "Login to Mixbook." Mixbook. Web. 26 Mar. 2012. .

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• By: Lindsey F.
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