Avogadro's Number
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Avogadro's Number
Can someone explain to me when we would multiply a unit by avogadros number and when we would divide by avogadros number
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Re: Avogadro's Number
We would multiply a unit by Avogadro's number if the weight, energy, etc. of a single atom were given and you wanted to find the weight, energy, etc. in mols. To find the weight, energy of a single atom you would divide the number of mols by Avogadro's number in order to figure out how much each atom has.
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Re: Avogadro's Number
We use Avogadro's number when converting from moles to atoms/molecules or vice versa. Depending on how you do your dimensional analysis, you can either divide or multiply by Avogadros number which has a unit of atoms/molecules.
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Re: Avogadro's Number
When going from moles to atoms/molecules, you would divide by Avogadro’s number, and when going from atoms/molecules to moles, you would multiply by Avogadro’s number.
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Re: Avogadro's Number
Just as a note for the final, I've noticed we've had to use Avogadro's number a lot during questions about the photoelectric effect. For example, if the question says the energy needed to remove an electron is 490 kJ/mol, you have to concert this into J/photon using Avogadros's number.
So, I'd say be extra careful with units and Avogadro's number with photoelectric questions! Of course be careful of units always though:)
So, I'd say be extra careful with units and Avogadro's number with photoelectric questions! Of course be careful of units always though:)
Re: Avogadro's Number
divide by Avogadro's # when going from moles -> atoms/molecules
multiply by Avogadro's # when going from atoms/molecules -> moles
multiply by Avogadro's # when going from atoms/molecules -> moles
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Re: Avogadro's Number
You would divide by Avogadro's number when converting from moles to atoms/molecule, and you would multiply by Avogadro's number when converting from atoms/molecule to moles.
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Re: Avogadro's Number
I could be wrong but shouldn't you multiply by Avogadro's number if you're trying to go from moles to molecules/atoms (i.e. 5 moles of carbon * 6.022*10^23 = number of atoms of carbon).
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Re: Avogadro's Number
In a more general sense, Avogadro's number is just the amount of objects in one mole. So if you were to set up a dimensional analysis table to solve a question, you should be using Avogadro's number as (6.0221*10^23)objects/mole
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Re: Avogadro's Number
Avogadro's number is used to describe the quantity of some object in one mol. As a result, you use Avogadro's number during some form of dimensional analysis relating to a mol. As for when you would divide or multiply by Avogadro's number, that can be determined by looking at the units of the previous value. For example, 1.008 g/mol has mol on the bottom so you would divide by Avogadro's number to find the mass of each hydrogen atom.
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Re: Avogadro's Number
The roadmap we've seen in stereochemistry explains the use of Avogadro's number. From going from moles to atoms or vice versa, Avogadro's number is the way to go.
Re: Avogadro's Number
What will be asked in a problem in order to know that we have to use this constant?
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