Observed in Illinois on the first Monday of March every year, the holiday ostensibly honors Polish-born Revolutionary War cavalry officer Casimir Pulaski, though for most school kids with a four-day week, itâs probably just another sweet, sweet sleep-in day.
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.
Elements are made up of only one type of atom. There are elements which are naturally occurring and those produced artificially in the laboratory. The elements Aluminum, Calcium, Helium, iron, Nitrogen, Potassium, Argon, Carbon, Gold, Hydrogen, Neon, Oxygen, Silver are some of the examples for pure substances.ntroduction to list of pure substances: A pure substance is that which consists of only one component with definite physical and chemical properties and with a definite composition. A pure substance may be either an element or a compound.