Empirical Formula

Front

What is an empirical formula?

Back

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

Front

How do you determine the empirical formula from percent composition?

Back

Convert the percentages to grams, then to moles, and find the simplest whole number ratio.

Front

What is the empirical formula of C2H4O2?

Back

The empirical formula is CH2O.

Front

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

Back

C2H4O2 and C6H12O6 both have the empirical formula CH2O.

Front

How many molecules are in 2.5 mol of NaCl?

Back

1.5 x 10^24 molecules.

Front

What is the molar mass of glycerol (C3H8O3)?

Back

The molar mass is 92.09 g/mol.

Front

What is the percent composition of glycerol?

Back

39.12% C, 8.75% H, and 51.12% O.

Front

What is the molecular formula for glycerol?

Back

C3H8O3.

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 in a molecule.

Front

What is the empirical formula for 40.05% S and 59.95% O?

Back

SO3.