Are these mixtures or pure substance?

1. water

2. blood

3. the oceans

4. iron 5. brass

6. uranium

7. wine

8. leather

9. table salt (NaCl)

A mixture is a system that is made up of two or more substances which are not combined chemically. A pure substance is a system that only has one substance. The following are classified as:

1. water : pure substance

2. blood : mixture

3. the oceans : mixture

4. iron : pure substance

5. brass : mixture

6. uranium : pure substance

7. wine : mixture

8. leather : mixture

9. table salt (NaCl) : pure substance