Molecular Formulas Review

Front

What is a molecular formula?

Back

A molecular formula shows the actual number and kinds of atoms present in one molecule of a compound.

Front

What is an empirical formula?

Back

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

Front

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

Back

To find the molecular formula, divide the molecular mass by the empirical formula mass and multiply the subscripts in the empirical formula by that ratio.

Front

Given the empirical formula NH2 and a formula mass of 32.06 amu, what is the molecular formula?

Back

N2H4.

Front

What is the empirical formula for C2F6?

Back

CF3.

Front

What is the molecular formula for K2SO4 with a molecular mass of 696g?

Back

K8S4O16.

Front

If a compound contains 67.1% zinc and the rest is oxygen, what is the empirical formula?

Back

ZnO2.

Front

What is the formula mass of a compound?

Back

The formula mass is the sum of the atomic masses of all atoms in a formula.

Front

How do you convert percentage composition to an empirical formula?

Back

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

Front

What is the difference between ionic and covalent formulas?

Back

Ionic formulas represent compounds formed by ionic bonds, while covalent formulas represent compounds formed by covalent bonds.