Symbols, formulae and equations - (CCEA)Compounds

Symbols, formulae and equations help chemists to explain chemical reactions in detail.

Part ofCombined ScienceStructures, trends, chemical reactions, quantitative chemistry and analysis

Compounds

A compound is two or more elements that are chemically combined.

The table below shows some common compounds.

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

Interpreting formulae

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