Yes, in chemistry a pure substance means either an element or a compound. Thus, hydrogen, oxygen, sodium, iron, copper etc. are pure substances; and so are compounds such as water, sugar, ammonia, sodium chloride, methane, ethanol etc. A compound is composed of two or more elements combined in a fixed ratio by mass. Like an element, a compound also has a distinct chemical identity. A mixture is not a pure substance as it is a collection of two or more elements/compounds in varying ratio. Air, sea water, gasoline, vegetable oils, steel etc. are mixtures.
Hudson (CDP), Massachusetts. Hudson is a census-designated place (CDP) in the town of Hudson in Middlesex County, Massachusetts, United States. The population was 14,907 at the 2010 census.
Zone 2) Suburban Area. (7 sq. miles and growing). This central area of Hudson, located from the east side of US 19 to Hicks Rd., and from SR 52 in the south to County Line Rd. in the north, consists of beautiful, large master-planned subdivisions with golf courses and private clubhouses.