Percent Composition Empirical and Molecular Formulas

What is the molecular formula of a compound with an empirical formula of C₂OH₄ and a molar mass of 88 grams per mole?

• C₂O₄H₈

• C₈O₂H₄

• C₄O₂H₈

• C₄O₈H₂

What is the molecular formula if the empirical formula is C₂H₅ and the molecular molar mass is 58.14 g/mol?

• C₂H₅

• C₄H₁₀

• C₁H_2.5

• C₄H₈

Which of the following is considered an empirical formula?

• CH₃COOH

• C₆H₁₂O₆

• H₂O

Tags

NGSS.MS-PS1-1

2.40 g of an explosive, J, contains 0.473 g of nitrogen. J also contains 33.8% carbon and 1.41% hydrogen by mass. The remainder of J is oxygen.

What is the empirical formula of J?

• C₄HNO₂

• CH₂N₂O

• C₂HNO₂

• CHNO

Tags

NGSS.MS-PS1-1

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%

What percentage of the total atomic mass of magnesium bromide (MgBr₂) is composed of bromine? Hint - consider the mass of both atoms of bromine in your calculation.

• 13%

• 43%

• 63%

• 87%

What percentage of the total atomic mass of lithium phosphide (Li₃P) is composed of lithium? Hint - consider all three atoms of lithium in your calculation.

• 13%

• 29%

• 40%

• 60%

Tags

NGSS.HS-PS1-7

What percentage of the total atomic mass of calcium nitrate (Ca(NO₃)₂) is composed of nitrogen? Hint - another way to think of calcium nitrate is Ca(NO₃)(NO₃).

• 17%

• 24%

• 29%

• 59%

What is the percent composition of carbon in carbon dioxide (CO_2)?

• A) 27%

• B) 33%

• C) 40%

• D) 73%

Tags

NGSS.MS-PS1-1