Empirical Formula Practice
A 100 gram sample of
compound of sodium contains 36.5 grams of sodium, 25.4 grams of sulfur, and
38.1 grams of oxygen. Does the empirical formula for the compound lead you to
believe it is sodium sulfite or sodium sulfate?
Fat makes up a major
portion of all soaps. A fat used in many soaps is 76.5% carbon, 12.2%
hydrogen, and 11.3% oxygen
What is its empirical
What is the molecular
formula of a fat with a molecular mass of 705 u?
A sample of a substance is
determined to be composed of 0.89 grams of potassium, 1.18 grams of chromium,
and 1.27 grams of oxygen. Calculate the empirical formula of this substance.
Strychnine, a deadly
poison, has a molecular mass of 334 amu and a percentage composition of 75.42%
carbon, 6.63% hydrogen, 8.38% nitrogen, and the balance oxygen. What is the
molecular formula of strychnine?
(Hint: DO NOT round up
the number found for carbon in the empirical formula.)
A 10 gram sample of a
compound contains 7.22 grams of magnesium and 2.78 grams of nitrogen. What is
its empirical formula?
An organic compound with a
molecular mass of 140u is 68.54% carbon, 8.63% hydrogen, and 22.83% oxygen.
What is the molecular formula of the compound?
To find the experimental
empirical formula of a compound, a student heats a coil of magnesium ribbon
35.00 cm long in a crucible. Water is added to the ash left in the crucible
and the crucible is reheated until dry.
Data from the experiment:
Mass of empty crucible
and cover - 20.74g
Mass of one meter of
magnesium ribbon - 0.72g
Mass of crucible, cover,
and final product - 21.17g
What is the empirical
formula for the oxide of magnesium that was the final product?