Empirical Formula: Simplest Whole Number Ratio of Atoms in a Substance

The video tutorial explains the concepts of empirical and molecular formulas, highlighting their differences and similarities. It covers how to convert molecular formulas to empirical formulas by finding common factors and provides examples using compounds like water, ethane, and butadiene. The tutorial also demonstrates how to determine empirical formulas from the masses of elements in a compound, using examples like iron bromide and vanadium oxide. Finally, it explains how to convert empirical formulas back to molecular formulas using relative formula mass.

What is the empirical formula of water?

• HO

• H2O

• H2O2

• H3O

Which of the following is true about empirical formulas?

• They are always more complex than molecular formulas.

• They are used only for ionic compounds.

• They always match the molecular formula.

• They represent the simplest whole number ratio of atoms.

How can you convert a molecular formula to an empirical formula?

• By rearranging the atoms in the formula.

• By multiplying the subscripts by two.

• By finding and dividing by the highest common factor.

• By adding more atoms to the formula.

What is the empirical formula of hydrazine (N2H4)?

• N2H2

• NH2

• NH3

• N2H4

In the example of butadiene (C4H6), what is the empirical formula?

• CH

• C2H6

• C4H6

• C2H3

How do you determine the empirical formula from experimental data?

• By converting masses to moles and finding the simplest ratio.

• By measuring the volume of the compound.

• By observing the color change in a reaction.

• By using the boiling point of the compound.

If the empirical formula mass is 14 and the relative formula mass is 140, what is the molecular formula if the empirical formula is C2H2?

• C20H40

• C4H4

• C10H20

• C2H2