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.
1 Ammonia has alkaline properties and is corrosive. 2  Ammonia gas dissolves easily in water to form ammonium hydroxide, a caustic solution and weak base. 3  Ammonia gas is easily compressed and forms a clear liquid under pressure.4  Ammonia is usually shipped as a compressed liquid in steel containers.ome chemical/physical properties of ammonia are: 1  At room temperature, ammonia is a colorless, highly irritating gas with a pungent, suffocating odor. 2  In pure form, it is known as anhydrous ammonia and is hygroscopic (readily absorbs moisture). 3  Ammonia has alkaline properties and is corrosive.