Thursday, February 18, 2010

Sample Of Welcomepeech How Would You Do The Math For The Number Of Atoms In A Sample Of 135 Mg Of Selenium?

How would you do the math for the number of atoms in a sample of 135 mg of selenium? - sample of welcomepeech

I am working on my homework and I think that the chemistry to calculate the number of atoms in a sample of 135 mg of selenium ... How do I do that math for that?

3 comments:

Bieber said...

135/the mass of the atom (in mg) = amount.

I'm not sure what selenium is difficult, but ... But it will help a bit:)
And BTW, this is just another shower .... made me facepalm: P

turquesa... said...

1 - It is necessary to work with SI units for work ... 135mg = 0.135g
2 - You also need the MM (molecular weight) of selenium, 78.96 (, g / mol)
3-1 mol = 6.02x10 ^ 23 particles (atoms or molecules in the subject matter). In this case atoms.
4 - Now you have everything you need:
0.135g • IS 1mol · Se/78.96g is 6.02x10 ^ 23 atoms / 1 mol
5-You and operations units of the cross and the answer would be:
1.03x10 ^ 21 (which makes sense because it is much less than 135 mg per mole)

Randy P said...

Find the atomic weight of selenium, lord of the mass of Avogadro number of atoms of selenium, 6.02 23. x 10 ^

Therefore, 135 / M = n / (6.02 x 10 ^ 23)

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