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.
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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)
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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. Suppose a mole of marshmallows fell upon the planet,
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This note was uploaded on 07/30/2008 for the course BIO 201 taught by Professor Janicke during the Spring '08 term at SUNY Buffalo.

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

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