# Chemistry

posted by Annabelle

2) What is the empirical formula of a compound containing C, H, O if combustion of 1.23g of the compound yields 1.8g CO2 and .74g of H2O

3) What are the empirical and molecular formulas of a hydrocarbon if combustion of 2.10g of the compound yields 6.59g CO2 and 2.7g H20 and its molar mass is about 84g/mol

I really do not understand the steps to do this. I understand the standard way going from grams to moles then I do not know what to do with the values I calculate.

1. DrBob222

OK. Step by step #2 and I'll assume you know how to get from grams to mols.
6.59g CO2 = 0.150 mols CO2 = 0.150 mols C.
2.7 g H2O = 0.150 mols H2O = 0.300 mols H(atoms)
So now we have
0.150 g C
0.300 g H

We want to find the ratio, in small whole numbers, with no number being smaller than 1.00. The easy way to do that is to divide the smaller number by itself.
C = 0.150/0.150 = 1.00. That way assures us of getting 1.00 for the smaller number.
Then divide all of the other numbers (just one other one in this problem but many will have more than one).
0.300/0.150 = 2.00
So the ratio is C1.00H2.00 but we don't right the 1.00 and we would show CH2 for the empirical formula.

#1 you must convert mols CO2 and mols H2O to grams C, grams H and find O by total mass -mass C - mass H = mass O.

Then launch into the above to find the ratio. If you get stuck show your work and explain what you don't understand about the next step.

## Similar Questions

1. ### Chemistry- Empirical Formula

Aniline, consists of C, H, and N. Combustion of such compounds yields CO2, H2O, and N2. If the combustion of 9.71 mg of aniline yields 6.63 mg H2O and 1.46 mb N2, what is the empirical formula?
2. ### chem

combustion analysis of a 285.7 mg sample of a hydrocarbon produces 880.8 mg of CO2 ans 405.7 mg of H2O. What is the empirical formula of the compound?
3. ### Chemistry

0.717 g of a compound containing carbon, hydrogen, and oxygen is burned and found to produce 1.02 g CO2 and 0.624 g H2O. The molar mass of the compound is 124 g/mol. (a) Write a chemical equation for the combustion of this unknown …
4. ### chemistry

Combustion analysis, Empirical and Molecular formulas, help!?
5. ### Chemistry

A compound containing only C, H, and O was extracted from the bark of the sassafras tree. The combustion of 36.3mg produced 98.6 of CO2 and 20.2mg of H2O. The molar mass of the compound was 162 g/mol. Determine its empirical and molecular …
6. ### Chemistry

A compound containing only C, H, and O was extracted from the bark of the sassafras tree. The combustion of 36.3mg produced 98.6 of CO2 and 20.2mg of H2O. The molar mass of the compound was 162 g/mol. Determine its empirical and molecular …
7. ### chemistry

"empirical formulas" combustion of a 0.255g compound conatining only C,H and O, yields 0.561g CO2 and 0.306g H2O. what is the empirical formula of the compound?
8. ### chemistry

The combustion of a compound which contains only C and H yields 2.58 g of CO2 and 0.53 g of H2O. What is the empirical formula of the compound?
9. ### chem

When 3.517 grams of a hydrocarbon, CxHy, were burned in a combustion analysis apparatus, 11.59 grams of CO2 and 3.164 grams of H2O were produced. In a separate experiment, the molar mass of the compound was found to be 40.06 g/mol. …
10. ### chemistry

A 8.408 gram sample of an organic compound containing C, H and O is analyzed by combustion analysis and 12.53 grams of CO2 and 3.849 grams of H2O are produced. In a separate experiment, the molar mass is found to be 118.1 g/mol. Determine …

More Similar Questions