# Stoichiometry

4. Vitamin C, M= 176.12 g/mol, is a compound of composed of carbon, hydrogen, and oxygen. Vitamin C is found in many natural sources especially citrus fruits. When a 1.000-g sample of vitamin C is burned in a combustion apparatus 1.50 g of CO2 and 0.410 g of H2O are produced. What is the empirical formula of Vitamin C? What is the molecular formula of Vitamin C?

1. 👍
2. 👎
3. 👁
1. I assume M stands for molar mass.
CxHyOz + O2 --> CO2 + H2O
Convert g CO2 to g C and g H2O to g H.
1.50 g CO2 x (M C/M CO2) = 1.50 x 12/44 = 0.409
0.410 g H2O x (2*1/18) = 0.0455
g O = 1.00 - g C - g H = 1.00 -0.409 - 0.0455 = 0.545 g O
Convert to mols.
mols C = 0.409/12 = 0.0341
mols H = 0.0455/1 = 0.0455
mols O = 0.545/16 = 0.0341
Now you want to find the ratio of C to H to O with no number being less than 1.0. The easy way to start is to divide everything by the smallest number.
C = 0.0341/0.0341 = 1.00
H = 0.0410/0.0341 = 1.33
O = 0.0341/0.0341 = 1.00
These numbers are not small whole numbers so we multiply by integers to obtain, when rounded, small whole numbers.
For example, multiply by 2 to get
C = 0.0341/0.0341 = 1.00 x 2 = 2
H = 0.0455/0.0341 = 1.33 x 2 = 2.66
O = 0.0341/0.0341 = 1.00 x 2 = 2.00
Doesn't work so try 3.
C = 0.0341/0.0341 = 1.00 x 3 = 3.00
H = 0.0455/0.0341 = 1.33 x 3 = 3.99
O = 0.0341/0.0341 = 1.00 x 3 = 3.00
So the empirical formula is C3H4O3 and empirical mass is 88
The molecular formula is always an integer x empirical mass so
empirical mass x integer = 176.12 and round to whole number.
88 x integer = 176.12
integer 176.12/88 = 2.001 which rounds to 2.00 as a whole number so the molecular formula is (C3H4O3)2 = C6H8O6.

1. 👍
2. 👎
👤
DrBob222
2. I thought you needed to add 0.409 +0.0455 and then subtract them from 1.00? Why did you subtract all of them?

1. 👍
2. 👎

## Similar Questions

1. ### CHEM

A 0.4647-g sample of a compound known to contain only carbon, hydrogen, and oxygen was burned in oxygen to yield 0.8635 g of CO2 and 0.1767 g of H2O. What is the empirical formula of the compound? i got C3H3O2 IS IT RIGHT?

2. ### C hemistry

An unknown compound contains only carbon, hydrogen, and oxygen . Combustion of 2.50 g of this compound produced 3.67 g of carbon dioxide and 1.50 g of water. What is the empirical formula of a substance that contains 8.33×10−2

3. ### Chemistry

A compound that is composed of only carbon and hydrogen contains 80.0% C and 20.0% H by mass. What is the empirical formula of the compound?

4. ### Chemistry

"Given that the bond enthalpy of the carbon-oxygen bonds in carbon monoxide and carbon dioxide are 1073 kJ/mol and 743 kJ/mol respectively, and that of the bond in the oxygen molecule is 496 kJ/mol, calculate the enthalpy change

1. ### Chemistry

A compound containing only carbon, hydrogen and oxygen is subjected to elemental analysis. Upon complete combustion, a .1804g sample of the compound produced .3051g of CO2 and .1249g of H2O. What is the empirical formula of the

2. ### chemistry

You take an aspirin tablet (a compound consisting solely of carbon, hydrogen, and oxygen) with a mass of 1.00 g, combust it under an oxygen atmosphere, and collect 2.20 g of carbon dioxide and 0.400 g water. The molar mass of

3. ### Chemistry 1201

An unknown compound contains only carbon, hydrogen, and oxygen (C?H?O?). Combustion of 6.50 of this compound produced 9.53 g of carbon dioxide and 3.90 g of water. 1) How many moles of Carbon? 2) How many moles of Hydrogen?

4. ### Chemistry

What is the percent by mass of C in methyl acetate (C3H6O2)? The molecular weight of carbon is 12.0107 g/mol, of hydrogen 1.00794 g/mol, and of oxygen 15.9994 g/mol. Answer in units of %. Please work it out for me so I totally

1. ### chemistry

An unknown compound contains only carbon, hydrogen, and oxygen (CxHxOx). Combustion of 3.50G of this compound produced 5.13G of carbon dioxide and 2.10G of water A.How many moles of carbon, , were in the original sample? b. How

2. ### chemistry

Upon combustion, 4.30 grams sample of a compound containing only carbon, hydrogen, and oxygen produced 8.59 g of CO2 and 3.52g of H2o. what is empirical formula of the compound ?

3. ### chem

Combustion reactions involve reacting a substance with oxygen. When compounds containing carbon and hydrogen are combusted, carbon dioxide and water are the products. Using the enthalpies of combustion for C4H4 (-2341 kJ/mol),

4. ### chemistry

Fumaric acid, which occurs in many plants, contains, by mass, 41.4% carbon, 3.47% hydrogen, and 55.1% oxygen. A 0.050-mol sample of this compound weighs 5.80 g. The molecular formula of this compound is can you show me the formula