posted by manny on .
Hi the following comes from my first homework assignment in AP Chemistry. I am totally lost on this question and don't know where to start. Thanks a lot in advance!!!!!
A 0.1247 g sample of ascorbic acid, Vitamin C, was burned in a carbon-hydrogen combustion apparatus to produce 0.1869 g of carbon dioxide, and 0.0510 g of water. Ascorbic acid contains only carbon, hydrogen, and oxygen. Determine the masses of C,H, and O in the sample and then determine the simplest formula.
Convert 0.1869 g CO2 to g C.
0.1869 g CO2 x (1 mol C/1 mol CO2) = ?? g C.
Convert 0.0510 g H2O to g H.
0.0510 g H2O x (2 mols H/1 mol H2O) = ?? g H
Determine g oxygen by adding g C and g H and subtracting from the 0.1247 g sample initially taken.
Then the simplest (empirical formula) is determined by converting g C, H, and O to mols
mols C = g C/atomic mass C = xx mols C.
mols H = g H/atomic mass H = xx mols H.
mols O = g O/atomic mass O = xx mols O.
Now find the ratio of the three in simplest numbers; i.e., divide the smallest number by itself (thereby making it 1.00) and divide the other two numbers by the smallest number. Post your work if you get stuck.