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.
Columbia County is a county located in the U.S. state of New York. As of the 2010 census, the population was 63,096. The county seat is Hudson. The name comes from the Latin feminine form of the name of Christopher Columbus, which was at the time of the formation of the county a popular proposal for the name of the United States of America.