posted by Chris .
Could you please tell me if these are right?
How many moles are in the following.
A.) 80.0 g of NaOH I got 2.0 moles.
B.) 12.0 g of Ca(OH)2 I got 0.16 moles.
Write the simplest formula for each of the following compounds.
A.) 0.200 mole Al and 0.600 Cl. I got AlCl3
B.) 0.080 mole Ba, 0.080 mole S, 0.320 mole O. I got BaSO4
You threw away two perfectly good numbers for the first two.
80.0/39.997 = 2.000 which rounds to 2.00 to three significant figures (you are allowed 3 from the 80.0).
12.0/74.093 = 0.16196 which rounds to 0.162 to three s.f. (3 s.f. allowed by the 12.0)
The other two are ok.