How to separate these pure substance?if it is not possible, please write cannot be separate Oxgen
Water
Gold
Carbon Dioxide
Carbon

Oxgen- cannot be separated

Water - chemical change

Gold - cannot be separated

Carbon Dioxide - chemical change

Carbon - cannot be separated

Explanation:

A pure substance, which can either be an element or a compound, contains only one type of such element or compound. In opposition to a mixture, pure substances cannot be separated by physical means.

- Elements as a pure substance cannot be separated because it contains only one type of atom. However, compounds contain two or more types of atoms, and hence, can only be separated into its individual atoms via chemical means.

In this question, oxygen (O2), Gold (Au) and carbon (C) are all elements and hence cannot be separated. Carbon dioxide (CO2) and water (H2O) are compounds because they contain two different atoms respectively, hence, can be separated into individual atoms.

it is the most commonly accepted one