A hydrocarbon was analyzed to be 5.7 mass percent hydrogen and 14.3 mass percent hydrogen. At 26 degrees Celcius and 75 torr pressure a sample with a volume of 1.13 L had a mass of 1.904 grams. Determine the molecular formula.
2007-11-04 13:09:19 · 2 answers · asked by Dan S 1 in Science & Mathematics ➔ Chemistry
Yeah... what Reb said.
2007-11-04 13:17:29 · answer #1 · answered by sardonic_manipulations 2 · 0⤊ 0⤋
First you need the empirical formula.
Divide each of the percentages by the respective molecular mass. You will have the mole ratio. Convert to whole numbers and you have the empirical formula.
Now use the ideal gas equation PV=nRT to solve for the moles of the molecule. You have the other data points for this formula.
Once you have the moles (you already have the grams) you can calculate the molecular mass. Now compare to the empiricial formula from above and finally get the molecular formula.
2007-11-04 13:15:21 · answer #2 · answered by reb1240 7 · 0⤊ 0⤋