chemistry aspirin?

Question

Ibuprofen has formula C13H18O2

a) how many atoms of carbon are in .425g

.425g(1moleC/12.01gC)(6.022 x 10^23 atoms of C/1 moleC)= 2.13 x 10^23atoms of carbon

b) how many grams of H are in 3.75 x 10^22 molecules of Ibuprofen
3.75 x 10^23 molecules (1 mole of Ibuprofen/6.022x10^23 atoms of Ibuprofen) (18 moles of H/1 mole of Ibuprofen) (1.008g H/1 mole H)

are those right?

Answer 1

B is right, but A isn't. BTW: when talking about elements, the proper term is g-atoms, not moles.
To get your answers, you have to convert your grams to moles. For this compound, Mole wt=
156+18+32=206. Soooo. moles=.425/206=MIP
For each mole of IP, there are 13 g-atoms of carbon. So to get atoms
MIP*13*6.02x10^23.

Part (b). Find the moles in the number of molecules. We know that Avagadro's #= 1mole
So moles of ibuprophen=3.75x10^22/6.02x10^23=MIP2
From the formula, we know that each mole contains 18g-atoms of H. So............
Grams of H= MIP2*206g/g-mole*(18/206)