Discussion 2 - key (1)

# Discussion 2 - key (1) - The mass of boron-10 is 10.01294...

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Key for Discussion Worksheet 2 Symbol Z A Number of Protons Number of Electrons Number of Neutrons Charge C 6 6 6 6 6 0 S 2- 16 32 16 18 16 -2 Ag + 47 108 47 46 61 +1 137 Ba 2+ 56 137 56 54 81 +2 31 P 15 31 15 15 16 0 N 3- 7 14 7 10 7 -3 4 He 2 4 2 2 2 0 + 2 25 12 Mg 12 25 12 10 13 +2 16 O 2- 8 16 8 10 8 2- 31 P 3- 15 31 15 18 16 -3

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1. A penny has a thickness of approximately 1.0 mm. If you stacked Avogadro’s number of pennies one on top of the other on Earths surface, how far would the stack extend (in km)? km x mm km mole pennies x penny mm mole 17 23 10 0 . 6 1000 1 10 022 . 6 0 . 1 1 = 2. The mass of an average blueberry is 0.75 g and the mass of an automobile is 2.0 x 10 3 kg. Find the number of automobiles whose total mass is the same as 1.0 mol of blueberries. cars x kg car g kg mole s blueberrie x blueberry g mole 17 23 10 3 . 2 2000 1000 1 10 022 . 6 77 . 0 1 = 3. Boron has only two naturally occurring isotopes.
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Unformatted text preview: The mass of boron -10 is 10.01294 amu and the mass of boron-11 is 11.00931 amu. Use the atomic mass of boron to calculate the relative abundances of the two isotopes. 199 . 801 . 01294 . 10 00931 . 11 01294 . 10 811 . 10 00 . 1 1 1 2 1 2 2 1 2 2 1 1 = =--=--= + = + = w m m m M w w w m w m w M w w 10 B – 19.9% and 11 B – 80.1% 4. Gallium has two naturally occurring isotopes: Ga-69 with a mass of 68.9256 amu and a natural abundance of 60.11%, and Ga-71. Use the atomic mass of gallium listed in the periodic table to find the mass of Ga-71. ( 29 amu w m w M m w w w m w m w M w w 92 . 70 3989 . 6011 . * 9256 . 68 723 . 69 3989 . 7092 . 000 . 1 00 . 1 2 1 1 2 2 2 1 2 2 1 1 =-=-= =-= + = + =...
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Discussion 2 - key (1) - The mass of boron-10 is 10.01294...

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