3) In hardware design, a prototype is a hand-built model that represents a manufactured (easily replicable) product sufficiently for designers to visualize and test the design. The word prototype comes from the Latin words proto, meaning original, and typus, meaning form or model.
In chemistry, a salt is an ionic compound which is made up of two groups of oppositely charged ions. The ion with a positive charge is called a cation, and the one with a negative charge is called an anion.
Salt is a compound made from Sodium and Chlorine. Its chemical formula is NaCl. Although made from two separate elements, a handful of salt is a pure substance not a mixture because it is a compound. Salt is a compound made from Sodium and Chlorine. Its chemical formula is NaCl.  Although made from two separate elements, a handful of salt is a pure substance not a mixture because it is a compound.