Suppose a piece of silver jewelry contains 5.44×1022 atoms of silver (Ag).

How many moles of silver atoms are in the piece of jewelry?




Calculate the number of moles of aluminum, sulfur, and oxygen atoms in 4.00moles of aluminum sulfate, Al2(So4)3

the numbers are subscript in the 2nd question

This post was edited by fingerling on Mar 2 2013 02:18pm

wow that's not much silver! Smaller than a spec of dust. And I thought I was a cheapskate when it came to jewellery!

But seriously I think that is supposed to be:
5.44*10^22


This post was edited by Azrad on Mar 2 2013 03:19pm

first count the number of atoms of each thing:
Al = 2
S = 3
O = 12
--------------------
x = g/mol of Al
y = g/mol of S
z=g/mol of O
a = number moles of substance

now we write an equation that describes the masses
2a*x+ 3a*y + 12a*z = 4 grams
(you can look up the value of x, y, and z on a periodic table and just plug them in, then solve for a)

once you have the value for a

moles of Al = 2a
moles of S = 3a
moles of O=12a

probably a much easier way to do this, but I was a rebel in chemistry and did things my own way.

maybe someday I'll post my algorithm for balancing any chemical equation without thought.

This post was edited by Azrad on Mar 2 2013 03:36pm

wow nvm tht is way too complicated.

answwer is super simple apparently..

literally jus take the moles they give u 4.0 in that problem * # atoms of the element.

al - 2 * 4mole
s-3 * 4mole
o-12 * 4 mole

y would u do it that way

This post was edited by fingerling on Mar 2 2013 04:40pm

oh i misread the problem, i thought it say 4 grams of Al2(SO4)3, not 4 moles. Well sooner or later you'll get a problem like this where they don't give you the moles.