Empirical and Molecular Formulas

Front

What is an empirical formula?

Back

An empirical formula represents the simplest whole-number ratio of atoms of each element in a compound.

Front

What is a molecular formula?

Back

A molecular formula shows the actual number of atoms of each element in a molecule of a compound.

Front

How do you derive the empirical formula from a molecular formula?

Back

To derive the empirical formula, divide the subscripts in the molecular formula by their greatest common divisor.

Front

Given the molecular formula Si2F6, what is the empirical formula?

Back

SiF3.

Front

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

Back

C2H4O2 and C6H12O6.

Front

If the empirical formula is CH2O and the molar mass is 180 g/mol, what is the molecular formula?

Back

C6H12O6.

Front

What is the empirical formula of K2SO4?

Back

K2SO4.

Front

How many carbon atoms are in C18H34O3?

Back

18.

Front

What is the relationship between empirical and molecular formulas?

Back

The empirical formula is a simplified version of the molecular formula, showing the ratio of elements.

Front

How can you determine the empirical formula from percent composition?

Back

Convert the percent composition to grams, then to moles, and simplify the mole ratio.