Empirical Formula & Molecular Formula

The empirical formula of a given compound can be the same as its molecular formula.

• True

• False

The molecular formula for ionic compounds represents the simplest whole number ratio of the ions present.

• True

• False

The molecular formula mass for sulfur dioxide is 54 grams.

• True

• False

An empirical formula always has a number of atoms of each element which is less than or equal to that of the molecular formula.

• True

• False

A certain compound is analyzed and its empirical formula is found to be CH₂. What piece of additional information is needed to determine the molecular formula?

• The melting point

• The density

• The molecular mass

• The crystal structures

Which of the following is NOT an empirical formula?

• FeCl₂

• C₈H₁₈

• C₄H₈O

• C₃H₈

A compound with an empirical formula of CH₂ has a molar mass of 70 g/mol. What is its molecular formula?

• C₅H₁₀

• C₂H₄

• CH₂

• C₄H₈

What is the empirical formula of octanoic acid, C₈H₁₆O₂?

• C₂H₄O

• CH₂O

• C₄H₈O

• C₈H₁₆O₂

If the molecular weight of a salt is 168.36 g/mol and the percentage composition of the salt is 78.93% Cs and 21.08% Cl, which of the following is the molecular formula of the salt?

• CsCl

• CsCl₂

• Cs₂Cl

• None of the above

What is the empirical formula of a 25.0 g unknown compound with 2.22 g hydrogen and 17.80 g oxygen?