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anonymous
 4 years ago
HELP! I have a variety of materials and I have to measure the mass, and calculate the number of mole, the number of individual units (molecules/compounds), and the number of atoms for a variety of samples.
anonymous
 4 years ago
HELP! I have a variety of materials and I have to measure the mass, and calculate the number of mole, the number of individual units (molecules/compounds), and the number of atoms for a variety of samples.

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anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0I already have the mass of four materials: Chalk (CaCO3): 2.04 g, Water (H2O): 32.0 g, Iron (fe): 15.87 g Copper (Cu): 0.59 g I know how to find the molar mass (calculate the number of moles?) but I don't know how to calculate the number of individual units (molecules/compounds), and the number of atoms for a variety of samples.. Please help!!

JFraser
 4 years ago
Best ResponseYou've already chosen the best response.11 mole of anything is 6.022x10^23 humber of those things. 1 mole of calcium carbonate will have that many molecules of that substance. This means you can use the equality as a conversion factor: \[2.04g CaCO{_3} * (\frac{1mol CaCO{_3}}{100g CaCO{_3}})*(\frac{6.02x10{^2}{^3}molecules CaCO{_3}}{1mol CaCO{_3}}) \]

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Is number of entities (basically what you showed me where n=NA) the "number of individual units"? How do I find the number of atoms for a variety of samples? A teacher told me that I should just count how many atoms there are in a compound.. like say Al3O2, which means there are 3 Aluminum, and 2 oxygen or 5 in total.

JFraser
 4 years ago
Best ResponseYou've already chosen the best response.1A single molecular unit of something like Al2O3 has 5 atoms total, correct. 1 MOLE of Al2O3 will have 6.022x10^23 molecules, and also 2 moles of Al atoms and 3 moles of O atoms, for 5 MOLES of atoms total. A mole is a term of grouping, just like a dozen. If you had 1 dozen eggs, you'd have just as many THINGS as if you had 1 dozen elephants. The MASSES of those things would be very different, but the number of items would be the same.
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