Calculating Molecular and Empirical Formulas in Chemistry

This video tutorial explains how to calculate the molecular formula from the empirical formula. It begins by defining empirical and molecular formulas, using glucose as an example. The tutorial then outlines a two-step process to calculate the molecular formula, demonstrated with examples of CH and P2O5. A bonus concept is introduced, highlighting compounds with identical empirical and molecular formulas.

What is the empirical formula of glucose?

• C6H12O6

• CH2O

• C12H24O12

• CHO

Which of the following is the actual formula of glucose?

• C6H12O6

• C2H4O2

• CH2O

• C3H6O3

What is the first step in calculating the molecular formula from the empirical formula?

• Divide the molecular formula by the empirical formula

• Find the molar mass of the empirical formula

• Multiply the empirical formula by a whole number

• Find the ratio of the given mass to the empirical formula mass

If the empirical formula is CH and the molar mass is 78 g/mol, what is the molecular formula?

• C2H2

• C3H3

• C6H6

• C4H4

What is the molar mass of the empirical formula CH?

• 14 g/mol

• 12 g/mol

• 13 g/mol

• 15 g/mol

For the empirical formula P2O5 with a molar mass of 283.88 g/mol, what is the molecular formula?

• P2O5

• P4O10

• P6O15

• P8O20

What is the molar mass of P2O5?

• 170 g/mol

• 150 g/mol

• 142 g/mol

• 160 g/mol

Which of the following compounds has the same empirical and molecular formula?

• Methane

• Ammonia

• Sulfuric acid

• Glucose

Which compound has both its empirical and molecular formula as CH4?

• Sulfuric acid

• Water

• Methane

• Iron oxide

What is a common characteristic of sulfuric acid, iron oxide, and water regarding their formulas?

• Their molecular formula is twice the empirical formula

• They have no empirical formula

• Their empirical and molecular formulas are the same

• They have different empirical and molecular formulas