How many atoms of hydrogen are in 250 g of hydrogen peroxide (H2O2)? please explain.
2 Answers
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Find molecular weight of H2O2: 2(1.01) + 2(16.0) = 34.02 g/mole
Find number of moles in 250 g: (250 g)(1 mole/34.02 g) = 7.3486 moles
Number of hydrogen atoms = (2)(7.3486 moles) = 14.6972 moles H atoms
Number atoms = (14.6972 moles)(6.022 x 10^23 atoms/mole) = 8.851 x 10^24 atoms
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H = 1.0079 g /mol
O = 15.999 g/mol
so you figure out what one mol of H2O2 would be
2*1.0079 + 2*15.999 = 34.0138 /mol
that means 34.0138 grams is 6.023*10^23 molecules
so 250g/34.0138 = 7.35 mol's
so the number of molecules
= 6.023*10^23 * 7.35
= 4426905000000000000000000
= 4.427 *10^24 molecules of hydrogen peroxide
since 2 atoms of H per molecule times by 2
number of atoms of H in 250 grams H2O2 is
n = 8.854*10^24
6.023*10^23 is avogadros number that is the number of atoms of a gas in 22.4 L of gas at Standard temperature and pressure.
also
http://en.wikipedia.org/wiki/Avogadro_constant
good luck hope that helps