A compound is a chemical substance that forms when two or more different elements combine in a fixed ratio. Water (H2O), for example, is a compound that is made up of two hydrogen atoms for every one oxygen atom. Sodium chloride (NaCl) is a compound made up of one sodium atom for every chlorine atom.
Hudson, Iowa. Hudson is a city in Black Hawk County, Iowa, United States. The population was 2,282 at the 2010 census. The rural community of Hudson has grown in recent years and is included as a part of the Waterloo-Cedar Falls Metropolitan Statistical Area. Contents.
Hudson County, New Jersey. Hudson County, a county in the U.S. state of New Jersey, lies west of the lower Hudson River, which was named for Henry Hudson, the sea captain who explored the area in 1609. Part of New Jersey's Gateway Region in the New York metropolitan area, Jersey City is its largest city and county seat.