2007-01-17 05:28:10 · 5 answers · asked by cshirl07 1 in Science & Mathematics ➔ Chemistry
Al2(SO4)3
(27x2)+{[32+(16x4)]x3}
= 54+{[32+64]x3}
= 54+{96x3}
= 54+288
= 342
2007-01-17 12:34:05 · answer #1 · answered by Kemmy 6 · 0⤊ 0⤋
Atomic weights: Al = 27 S = 32 O = 16 Al2(SO4)3 = 342
Let molecule be called mc; let aluminum sulfate be called A.
1 mcA x 1 molA/6.02x10^23mcA x 342gA/1 molA = (342)/(6.02x10^23) = 56.8 x 10^-23 g = 5.68 x 10^-22 g
The first factor comes from Avogadro's number, which is the number of molecules in a mole, just as it is the number of atoms in a g-atom. The molecules cancel, leaving moles. The second factor comes from the molecular (formula) weight. The moles cancel, leaving grams.
2007-01-17 05:45:17 · answer #2 · answered by steve_geo1 7 · 0⤊ 0⤋
look for the answer to a similar qtn yesterday...
Look(and note) the atomoc wt of the constituent atoms from periodic table.
Add them up to get the molecular weight. For example, in Al2S3, molecular wt will be 2*atomoc wt of Al + 3*Atomic wt of S
now divide the molecular wt by avagadro number(6.023 x 10^23) to get the weight of one molecule in grams.
Happy calculating now!
2007-01-17 05:38:26 · answer #3 · answered by Sandeep K 3 · 0⤊ 0⤋
Al2(SO4)3
2 x Al
3 x S
12 x O
Sorry I don't have a periodic table in front of me, but you can look up the numbers for each element and do the math.
Edit: O.K., I just found on online.
Al = 26.98154
S = 32.06
O = 15.9994
Therefore, the molecular weight of Al2(SO4)3 is...
342.13588 g/mol
2007-01-17 05:37:05 · answer #4 · answered by Anonymous · 0⤊ 0⤋
Find its molecular weight and divide it by Avogadro's constant and that's it the weight of one molecule in grams.
2007-01-17 05:39:35 · answer #5 · answered by deflagrated 4 · 0⤊ 0⤋