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lec3spr08noclick

# lec3spr08noclick - Ch.2 and Lab 1 The nucleus of an atom...

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02_02_atomic number.jpg Atomic mass = 12 Atomic mass =1 Ch.2 and Lab 1: The nucleus of an atom contains positively charged protons and uncharged neutrons. The number depends on the element. The nucleus is surrounded by a cloud of orbiting electrons. In an atom, the number of electrons = the number of protons. A proton or neutron has a mass of one dalton. Electrons=zero daltons. protons Protons+neutrons

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How much does a proton weigh? - The same as a neutron - = About 1/(6.02214x10 23 ) g. (g is the abbrevation for grams.) So how much does 6x10 23 protons weigh? One gram. And 6x10 23 neutrons weighs a gram. 6x10 23 is Avogardro’s number because Avogadro figured it out.
6x10 23 of any type of atom weighs one gram times the total number of protons and neutrons per atom. Example: 6x10 23 carbon atoms weighs 12 grams (because they have 6x10 23 protons and 6x10 23 neutrons) . How about carbon 14? - That’s what we call an isotope of carbon. . - C 14 has 6 protons per atom (so it’s still c), but 8 neutrons. - So 6x10 23 carbon 14 atoms weigh 14 grams. Anybody getting sick of saying 6x10 23? That’s why we say a mole instead.

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Chorus: A mole is a unit, or have you heard, Containing six times ten to the twenty-third, That's a six with twenty-three zero's at the end, Much too big a number to comprehend. http://www.roomd113.com/mole%20song.htm What’s a mole? The mole is a counting unit. One mole of something contains Avogadro's number (approximately 6 X 10 23 of it. A mole is much like "a dozen " in that both are absolute numbers (having no units)
Say you had a mole of pennies to distribute 'round the world, Give to each of the five billion grownups, boys, and girls, There wouldn't be a single person down and out of luck, Cause everybody in the world would get a trillion bucks. 6x10 23 pennies / (5 x 10 9 people) = 6/5 x 10 14 = about 1 x10 14 pennies 1 x10 14 pennies (1 dollar/10 2 pennies) = 1x10 12 dollars 10 3 = thousand 10 6 = million 10 9 = billion 10 12 = trillion

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How much 6.02 x 10 23 of something weighs depends on what it is.
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