Empirical Formula and Percentage Composition

Which pair has the same empirical formula?

• NaCrO₄ and Na₂Cr₂O₇

• C₂H₄O₂ and C₆H₁₂O₆

• C₃H₆O₃ and C₂H₆O₂

• CH₄ and C₂H₆

What percentage of the total atomic mass of carbon monoxide (CO) is composed of oxygen?

• 29%

• 43%

• 57%

• 73%

What percentage of the total atomic mass of carbon monoxide (CO) is composed of carbon?

• 29%

• 43%

• 57%

• 73%

Epinephrine (adrenaline) is a hormone secreted into the bloodstream in times of stress. It contains 59.0% C, 7.15% H, 26.20%O, 7.65%N and has a molar mass of 183 g/mol. What is its molecular formula?

• C₉H₁₃NO₃

• C₅H₁₁N₃O₂

• C₈H₁₂NO₂

• C₇H₉N₂O

Tags

NGSS.HS-LS1-6

What is the general formula for the computation of percentage composition of the given element?

• % mass of element = mass of element in the compound divided by mass of the compound times 100

• % mass of element = mass of element in the compound divided by mass of the compound

• % mass of element = mass of element in the compound divided by 100

• % mass of element = mass of element in the compound

Which of the following is a correct statement about composition of compound?

• Percentage composition of compound tells you how many elements are present.

• Percentage composition of compound tells you the name of an element.

• Percentage composition of compound tells you the percentage of the mass

• Percentage composition of compound tells you the percentage of the mass made up by each element in compound.

The percentage composition of acetic acid is found to be 39.9% C, 6.7% H, and 53.4% O. Determine the empirical formula of acetic acid.

• CH₂O

• C₂H₄O₂

• C₆H₇N

• Hg₂O

Aniline, a starting material for urethane plastic foams, consists of C, H, and N. Combustion of such compounds yields CO₂, H₂O, and N₂ as products. If the combustion of 9.71 g of aniline yields 6.63 g H₂O and 1.46 g N₂, what is its empirical formula?

• CH₂O

• C₂H₄O₂

• C₆H₇N

• Hg₂O

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7

The ___________ is considered to be the simplest formula of a compound.

• Molecules

• Molecular formula

• Empirical formula

• Percentage composition

The _______ is equal to the ratio between the total mass of an element in the compound and the molar mass of the compound multiplied by 100.

• Molecules

• Molecular formula

• Empirical formula

• Percentage composition