Percent Composition/Empirical Formulas

What is the percent by mass of magnesium in MgO?

• 20%
• 40%
• 50%
• 60%

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

A compound consists of 72.2% magnesium(Mg) and 27.8% nitrogen(N) by mass. What is the empirical formula?

• Mg₄N₃
• MgN₂
• Mg₃N₂ 
• MgN

You are given the following percentages: 40.05% S and 59.95% O. Find the empirical formula for these elements.

• SO
• SO2
• SO3
• SO4

What is the empirical formula if you have 81.82% carbon and 18.18% hydrogen?

• C3H8
• CH4
• C2H2
• C4H10

Given the following: 42.07% Na, 18.89% P, and 39.04% O, determine the empirical formula.

•  NaPO2
• Na2PO3
• Na3PO4
• NaPO4

Which pair has the same empirical formula?

• NaCrO₄ and Na₂Cr₂O₇
• C₂H₄O₂ and C₆H₁₂O₆
• C₃H₆O₃ and C₂H₆O₂
• CH₄ and C₂H₆

Tags

NGSS.HS-PS1-7

How many moles are in 19.82 g Mg?

• 1.23 mol Mg

• 481.70 mol Mg

• 1.00 mol Mg

• 0.82 mol Mg

Tags

NGSS.HS-PS1-7

Determine the mass of 4.20 moles of C₆H₁₂

• 354 g

• 84 g

• 337 g

• 421 g