Question

water H2O is made up of different elements hydrogen and oxygen is this type of combination of mixture or a pure substance

Answer 1

H2O is a compound it cannot be a pure substance

Answer 2

Answer: The given compound (water) is a pure substance

Explanation:

A pure substance is defined as the substance which is formed by same or different type of atoms which are chemically combined in a fixed ratio by mass.

Compounds and elements are considered as pure substances

A mixture is defined as the substance which is made by mixing two or more substances in any ratio.  They can be separated by physical means.

Water $(H_2O)$ is formed by the combination of hydrogen and oxygen elements in z fixed ratio of 1 : 8 by mass. Therefore, it is considered as a compound.

Hence, the given compound (water) is a pure substance