Q. What is compound?
A compound is a substance which consists of two or more elements chemically combined. The elements in a compound aren't simply mingled together as they are in a mixture. In its place they are combined in a way such that the compound has properties that are different from those of the elements of which it is composed. Every compound is represented by a formula a combination of the symbols of the elements that make up the compounds. You may already recognize some chemical formulas such as H2O for water, NaCl for table salt and NH3 for ammonia.