Why is water considered a compound?
Water is considered as compound because:
(i) Water is composed of two elements:hydrogen and oxygen.
2H2 +O2 -->2H2O
(ii) The ratio of hydrogen and oxygen by mass in any sample of pure water is the same.
(iii) The properties of water are different from its constituent elements: hydrogen and oxygen.
(iv) Water can be decomposed by chemical means (e.g., electrolytically) into hydrogen and oxygen.