Understanding Percent Composition

What is the formula to calculate a percentage?

• Part divided by whole times 100%

• Whole divided by part times 100%

• Part plus whole times 100%

• Whole minus part times 100%

If a jar contains 7 red, 6 blue, 10 green, 3 orange, and 4 purple marbles, what is the total number of marbles?

• 40

• 25

• 35

• 30

What percentage of marbles in the jar are green?

• 23.3%

• 20.0%

• 33.3%

• 10.0%

In a water molecule (H2O), what percentage of the mass is due to hydrogen?

• 33.3%

• 88.8%

• 11.2%

• 50.0%

What is the total mass of a water molecule in grams per mole?

• 20.00 g/mol

• 22.02 g/mol

• 18.02 g/mol

• 16.00 g/mol

In glucose (C6H12O6), what is the percent composition by mass of carbon?

• 39.99%

• 50.00%

• 60.00%

• 70.00%

What is the molar mass of glucose in grams per mole?

• 150.18 g/mol

• 180.18 g/mol

• 200.18 g/mol

• 220.18 g/mol

In ammonium sulfate ((NH4)2SO4), what percentage of the mass is nitrogen?

• 48.42%

• 24.26%

• 6.11%

• 21.20%

What is the total mass of ammonium sulfate in grams per mole?

• 132.17 g/mol

• 150.17 g/mol

• 190.17 g/mol

• 170.17 g/mol

In ammonium sulfate, what percentage of the mass is due to oxygen?

• 6.11%

• 21.20%

• 48.42%

• 24.26%