Empirical and Molecular Formula

Front

What is an empirical formula?

Back

An empirical formula represents the simplest whole-number ratio of elements in a compound.

Front

How do you determine the molecular formula from the empirical formula?

Back

To find the molecular formula, divide the molar mass of the compound by the molar mass of the empirical formula, then multiply the subscripts in the empirical formula by this ratio.

Front

What is the empirical formula of a compound with the molecular formula C6H12O6?

Back

C2H4O2.

Front

What is the difference between empirical and molecular formulas?

Back

The empirical formula shows the simplest ratio of elements, while the molecular formula shows the actual number of atoms of each element in a molecule.

Front

If a compound has an empirical formula of CH2 and a molar mass of 42 g/mol, what is its molecular formula?

Back

C3H6.

Front

What is the empirical formula for N2S3?

Back

N2S3.

Front

What is the percent composition of a compound?

Back

Percent composition is the percentage by mass of each element in a compound.

Front

How do you calculate the percent composition of an element in a compound?

Back

Percent composition = (mass of element in 1 mole of compound / molar mass of compound) x 100.

Front

What is the empirical formula for a compound with a molar mass of 60 g/mol and an empirical formula of CH2O?

Back

C2H4O2.

Front

Which pair of compounds has the same empirical formula: NaCrO4 and Na2Cr2O7, or C2H4O2 and C6H12O6?

Back

C2H4O2 and C6H12O6.