Percent Composition and Chemical Formulas

What is the percent composition by mass of sulfur in the compound MgSO₄ (gram formula mass = 120 g/mol)?

• 20%
• 27%
• 46%
• 53%

What is the percent composition by mass of oxygen in the compound MgSO₄ (gram formula mass = 120 g/mol)?

• 20%
• 27%
• 46%
• 53%

In which compound is the percent composition by mass of Cl equal to 42%?

• HClO (gram formula mass = 52 g/mol)
• HClO₂ (gram formula mass = 68 g/mol)
• HClO₃ (gram formula mass = 84 g/mol)
• HClO₄ (gram formula mass = 100 g/mol)

What is the percent composition of Benzene, C₆H₆?

• C = 50%
  H = 50%
• C = 85.7 %
  H = 14.3%
• C = 92.2%
  H = 7.8%
• C = 71.9%
  H = 28.1%

What is the percent composition of aluminum phosphate?

• Al = 25%
  P = 25%
  O = 75%
• Al = 22.1%
  P = 35.8%
  O = 42.1%
• Al = 14.3%
  P = 25.4%
  O = 60.3%
• Al = 22.1%
  P = 25.4%
  O = 52.5%

What percent of Zn₃(PO₄)₂ is zinc?

• 33.15%

• 16.04%

• 50.80%

• 19.68%

What is the percent composition of a compound that contains 40.8 g carbon and 54.4 g oxygen?

• 42.9 %; 57.1% oxygen

• 52.9 %; 57.1% oxygen

• 42.9 %; 45.23% oxygen

• 55.9 %; 99.1% oxygen

Tags

NGSS.HS-PS1-7

If 45.0 g of Mg react with 19.5 g of oxygen, what is the % ofmagnesium in the resulting compound?

• 69.8%
• 30.2%
• 43.3%
• 12.9%

What is the Law of Conservation of mass?

• Mass is created in a chemical reaction
• Mass is created in a physical change
• New chemicals formed from a chemical reaction have a larger overall mass than the original reactants
• Mass is never created or destroyed

Tags

NGSS.HS-PS1-7

What is the percent by mass of Mn in KMnO₄?

• 50%

• 25%

• 35%

• 40%