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.
Sergeant Bluff is a city in Woodbury County, Iowa, United States. It is part of the Sioux City, IAâNEâSD Metropolitan Statistical Area. The population was 3,321 at the 2000 census. The city was named after Sergeant Charles Floyd, the only member of the Lewis and Clark Expedition to die on the journey. Sergeant Bluff is located at 42Â°24â²7â³N 96Â°21â²30â³W / 42.40194Â°N 96.35833Â°W / 42.40194; -96.35833 (42.402055, -96.358316).