Answer the following question given this paragraph: 

Silver and ordinary table salt are two examples of chemical substances . A substance is matter that has a uniform and definite composition. All samples of substances, sometimes called pure substances, have identical properties. When chemists run a chemical reaction, they want to use pure materials so they know exactly what they are dealing with. They know that the reaction involves a specific substance, so they expect the same reaction to give the same results each time it is run.


Q: Silver and ordinary table salt are two examples of chemical what?


A:
substances