Answer:
A pure substance is a form of matter that has a definite composition and distinct properties. It may consist of only one type of atoms (examples: Fe(s), N2(g), S8(s)), or of only one compound where the atoms are connected in a defined way, (examples: FeS(s), CH4(g), NaNO3(s), H2O(l)).
This question is rather easily answered if you answer using only elements: Hydrogen, Helium, Carbon, Gold, Silver, Oxygen, Nitrogen, Argon, Calcium, Potassium, etc.
Here are a few pure substances that are not elements, rather compounds: Methane, carbon monoxide, carbon dioxide, pure water and table salt (sodium chloride).
non-iodized table salt
sugar
water H20
baking soda - sodium bicarbonate
oxygen