[haloholdsmeback]

Determine the mass, in grams , of

1. 3.00 mole AL
   4.25 mole Li
   1.38 mole N
   8.075 mole Au
   6.5 mole CV
   2.57x10^8 mole S
   1.75x10 mole HG
   .00003 mole Fe

My teacher does not explain to the class and I have no idea how to do this I tried asking him but he just says ask a friend and my friends don't care about there education.
If some one could just explain to me how to do this that would be wonderful!

[BAMAstudent]

I'm going to show you know to do a couple of these and you should be able to follow the formula and solve the rest on your own.

the first one, 3.00 mole Al:
Using Avogadro's number you know that there are 6.022*10^23 molecules/mol. Therefore you divide 3.00 molecules of Al by 6.022*10^23mole/mol. This leaves you with 4.982*10^-24mol of Al. Now you can simply multiply by the molar mass of Aluminum(from the periodic table) 26.98g/mol which comes out to 1.34*10^-22grams of Al.

now 2.57*10^8 mole S
divide by Avogadro's number and get 4.27*10^-16 mol of S. Then multiply by the molar mass of Sulfur which is 32.07 g/mol. The answer comes out to be1.37*10^-14 g of S.


The important thing to remember about these problems is to pay attention to unit!! Make sure you cancel out units properly and everything will fit into place.

Hope this helped!! Roll Tide!