Question

calculate the number of C, N, O, and H atoms in 1.0 grams of C17H21NO4

Answer 1

molecular mass of \( C_{17}H_{21} NO_4= 17\cdot 12+21\cdot1+1\cdot15+4\cdot16\)

Answer 2

ok so molecular mass would be 304

Answer 3

right.
17*12 / 304 comes from C

21/304 comes from H

15/304 comes from N

4*16/304 comes from O

Answer 4

so carbon would have .67, Hydrogen would have .069, Nitroge would have 0.049 and Oxygen would have 0.211

Answer 5

are those all the correct # of significant figures??

Answer 6

thanks by the way!

Answer 7

sorry atomic mass of N is 14 not 15 ...

so it add to 303

Answer 8

haha so I just do everything over 303...no sweat. its 3 significant figures correct??

Answer 9

yes ... 303.353 if you want more precision

Answer 10

btw ... why am i helping helping you make 1g of cocaine ... lol

Answer 11

i swear its my chemistry homework...hahaha. so will my final answer be 3 sig figs? my teacher doesn't give ANY mercy with significant figures

Answer 12

1.0g is just 2 sig figs .... so you are good

Answer 13

@maggielucci : SORRY, this is the answer to the question you had asked earlier about % of C,H, N, O in the molecule (by mass)

Answer 14

so C is 0.67 or 67% by mass and so on

Answer 15

@maggielucci . for this one:

Once you have the molar mass of cocaine as 303 grams per mole. So you know 1.0g has 1.0/303 moles.

Since there are 17 C in every molecule, you have 1/303 *17 = 0.05604 moles of C

then multiply this by Avagadro number to get the number of C atoms.