a compound in chemistry, is any substance that is formed when two or more chemical elements are chemically bonded together. A prime example of this is H20. You are combining hydrogen to oxygen, giving you a compund element. I hope this helps you. :)
Answer: Argon (Ar), which has 18 protons.
Answer:
Lead is added to warm dilute nitric acid. When the carbonate has reacted with the warm acid, more carbonate is added until the carbonate is in excess.
Explanation: