Chemistry anyone?

Question

Calculate the Molecular Formula of a compund whose composition is 55.8% Carbon, 11.6% Hydrogen, and 32.6% Oxygen.

Calculate the Molecular Formula of a compund whose composition is 55.8% Carbon, 11.6% Hydrogen, and 32.6% Oxygen. I already know how to do all of the first steps, but the number of moles are NOT coming out to be whole numbers. I know that you convert to moles and divide by the lowest number. Just try to work the problem and see if you get a different answer.

The molecular weight is 171.0 amu.

Answer 1

Use % composition to find the empirical formula:

1) change % to grams. That way 100% = 100 g.
2) change grams to moles by dividing each mass by the molar mass of that element:

55.8 g C / 12 g per mol C = 4.65 mol C
11.6 g H / 1 g per mol H = 11.6 mol H
32.6 g O / 16 g per mol O = 2.04 mol O

3) divide each amount of moles by the smallest:

4.65 mol / 2.04 mol = 2.28
11.6 mol / 2.04 mol = 5.69
2.04 mol / 2.04 mol = 1

(these mol answers are unusual, perhaps there is more information you could give us? I will finish the best I can.)

4) since .28 is close to 1/4, and .69 is close to 3/4, multiply each answer by 4 to clear the denominator:

2.28 x 4 = 9
5.69 x 4 = 23
1 x 4 = 4

5) use these as your subscripts

C9H23O4

Answer 2

I see your problem... Check the question... perhaps the percents are off... otherwise the answer would be...


C228 H569 O100

This is not a real substance... check the question again...unless "Close" counts in your chem class.... then it's

C9 H23 O4

Doubtful...

Answer 3

I did the problem as you described (and as I know how) and I also did not get a rational answer.

I tried other solutions, which were
C 4.56, H 11.38, O 2
C 6.84, H 17.07, O 3

Answer 4

first convert these to moles and then divide every answer by the smallest answer