Determining the mass percent of the elements in a compound is useful to find the empirical formula and molecular formulas of the compound. This collection of ten chemistry test questions deals with calculating and using mass percent. The answers appear after the final question.
A periodic table
is necessary to complete the questions.
Question 1Calculate the mass percent of silver in AgCl.
Question 2Calculate the mass percent of chlorine in CuCl2.
Question 3Calculate the mass percent of oxygen in C4H10O.
Question 4What is the mass percent of potassium in K3Fe(CN)6?
Question 5What is the mass percent of barium in BaSO3?
Question 6What is the mass percent of hydrogen in C10H14N2?
Question 7A compound is analyzed and found to contain 35.66% carbon, 16.24% hydrogen and 45.10% nitrogen. What is the empirical formula of the compound?
Question 8A compound is analyzed and found to have a mass of 289.9 grams/mole and contain 49.67% carbon, 48.92% chlorine and 1.39% hydrogen. What is the molecular formula of the compound?
Question 9The vanillin molecule is the primary molecule present in vanilla extract. The molecular mass of vanillin is 152.08 grams per mole and contains 63.18% carbon, 5.26% hydrogen, and 31.56% oxygen. What is the molecular formula of vanillin?
Question 10A sample of fuel is found to contain 87.4% nitrogen and 12.6% hydrogen. If the molecular mass of the fuel is 32.05 grams/mole, what is the molecular formula of the fuel?