Compounds
A compoundA substance formed when two or more elements are chemically combined. is two or more elements chemically combined.
The table below shows some common compounds. It’s useful to know that mono means one, and di means two.
- carbon monoxide has one atom of oxygen
- carbon dioxide has two atoms of oxygen
| Compound | Formula | Elements present |
| water | H2O | hydrogen, oxygen |
| carbon monoxide | CO | carbon, oxygen |
| carbon dioxide | CO2 | carbon, oxygen |
| sulfur dioxide | SO2 | sulfur, oxygen |
| sulfur trioxide | SO3 | sulfur, oxygen |
| nitrogen monoxide | NO | nitrogen, oxygen |
| nitrogen dioxide | NO2 | nitrogen, oxygen |
| ammonia | NH3 | nitrogen, hydrogen |
| hydrochloric acid | HCl | hydrogen, chlorine |
| nitric acid | HNO3 | hydrogen, nitrogen, oxygen |
| sulfuric acid | H2SO4 | hydrogen, sulfur, oxygen |
| Compound | water |
|---|---|
| Formula | H2O |
| Elements present | hydrogen, oxygen |
| Compound | carbon monoxide |
|---|---|
| Formula | CO |
| Elements present | carbon, oxygen |
| Compound | carbon dioxide |
|---|---|
| Formula | CO2 |
| Elements present | carbon, oxygen |
| Compound | sulfur dioxide |
|---|---|
| Formula | SO2 |
| Elements present | sulfur, oxygen |
| Compound | sulfur trioxide |
|---|---|
| Formula | SO3 |
| Elements present | sulfur, oxygen |
| Compound | nitrogen monoxide |
|---|---|
| Formula | NO |
| Elements present | nitrogen, oxygen |
| Compound | nitrogen dioxide |
|---|---|
| Formula | NO2 |
| Elements present | nitrogen, oxygen |
| Compound | ammonia |
|---|---|
| Formula | NH3 |
| Elements present | nitrogen, hydrogen |
| Compound | hydrochloric acid |
|---|---|
| Formula | HCl |
| Elements present | hydrogen, chlorine |
| Compound | nitric acid |
|---|---|
| Formula | HNO3 |
| Elements present | hydrogen, nitrogen, oxygen |
| Compound | sulfuric acid |
|---|---|
| Formula | H2SO4 |
| Elements present | hydrogen, sulfur, oxygen |