Empirical Formula and Percentage Composition

Find the percent composition of Cu₂S?

• %Cu= 67.987 %S= 32.013

• %Cu= 79.854   %S= 20.145

• %Cu= 35.946   %S= 64.054

Tags

NGSS.HS-PS1-7

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

• Mg₄N₃

• MgN₂

• Mg₃N₂ 

• MgN

Which of the following is considered an empirical formula?

• CH₃COOH

• C₆H₁₂O₆

• H₂O

A formula with the lowest whole # ratio of elements in a compound is called

• Molecular Formula

• Chemical Formula

• Empirical Formula 

• Distance Formula

How would you calculate the percentage of Hydrogen?

d

c

a

100

2

18

16

What is the percent by mass of magnesium in MgO?

• 20%

• 40%

• 50%

• 60%

What is the approximate percent by mass of magnesium in MgO?

• 20%

• 40%

• 50%

• 60%

What is the empirical formula for a compound if it contains 70% iron (Fe) and 30% oxygen (O) by mass? Assume atomic masses: Fe = 56 g/mol, O = 16 g/mol.

• FeO

Tags

NGSS.HS-PS1-7

• 35.00%

• 28.13%

• 17.65%

• 22.22%

A compound contains 40% sulfur and 60% oxygen by mass. What is the empirical formula of the compound? Assume the molar mass of sulfur (S) is 32 g/mol and oxygen (O) is 16 g/mol.

• SO

Tags

NGSS.HS-PS1-1