Percent Composition and Moles

Find the percentage composition of Mg in Mg₃(PO₄)₂.

• 27.48% Mg

• 43.11% Mg

• 16.00% Mg

• 12.63% Mg

Which of the following is NOT needed to calculate percent composition?

• Mass of specific element

• Molar Mass

• Avogadro's Number

• Division

What is the percent by mass of sodium in NaCl?

• 39%

• 61%

• 35%

• 65%

What is the equation for calculating percent composition?

• mass of element/mass of compound = x 100

• mass of compound/mass of element = x 100 

• total mass/molar mass = x 100 

• molar mass/molar mass = x 100 

• 88.81%

• 11.19%

• 89.11%

• 10.89%

Tags

DOK Level 2: Skill/Concept

• 25.13%

• 74.87%

• 20.11%

• 79.89%

Tags

DOK Level 2: Skill/Concept

Which element in the compound will have the HIGHEST percent composition?

Tags

NGSS.HS-PS1-7

Complete the formula for % Composition.

a

b

c

100

mass of element

total mass of compound

Tags

NGSS.HS-PS1-7

The mass % of aluminum in aluminum sulfate Al₂(SO₄)₃ is:

• 12.93%

• 45.70%

• 7.89%

• 35.94%

• 15.77%

What is the percent composition of Nitrogen in NO₂? (rounded)

• 30%

• 40%

• 50%

• 60%