I looked up how to solve it but my answer is coming out wrong. I don't know what i'm doing wrong please help!.Now if your lab partner determined that there were 4.030 x 1020 atoms of H in an unknown sample of C2H4Cl2, how many milligrams would the unknown sample weigh?
Thanks, Bella :)
4.030x10^20 atoms is 0.0006691 moles
Each mole of the sample, contains 4 H atoms, so that means only .0001673 moles of the sample.
The mol wt of the sample is 2*12+4*1+2*35.45 = 98.9
.0001673*98.9 = 16.54 mg