Percent Composition

What is the percent by mass of oxygen in MgO? Hint: The attached image is an example of a worked problem other than this one.

• 20%

• 40%

• 50%

• 60%

Tags

NGSS.HS-PS1-7

What is the percent by mass of magnesium in MgO?

• 20%
• 40%
• 50%
• 60%

What is the percent by mass of fluorine in CaF₂ (gram-formula mass = 78 g/mol)?

• 24%
• 49%
• 51%
• 65%

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%

Tags

NGSS.HS-PS1-7

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)

Find the percent composition of Cu₂S?

• %Cu= 67.987 %S= 32.013
• %Cu= 79.854   %S= 20.145
• %Cu= 35.946   %S= 64.054

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%

Tags

NGSS.HS-PS1-1

What is the empirical formula for the following:
Pb₅Cr₅O₂₀

• Pb₂Cr₂O₁₀
• PbCr₂O₇
• Pb₉Cr₄O₂
• PbCrO₄

Which element has an abundance of 39.03% in the compound sodium phosphate, Na₃PO₄

• Na

• P

• O

• None of the above

Tags

NGSS.MS-PS1-1