Many pure metals like copper, iron and gold are very soft and as such are considered unsuitable for certain…
Many pure metals like copper, iron and gold are very soft and as such are considered unsuitable for certain uses. Metallic objects around us such as cooking utensils, statues, ornaments, guns etc. are actually not made up of pure metals. Instead of pure metals, alloys are used in the design of most of the useful objects. Making alloys enhances the basic properties of a metal which is the primary constituent (metal) of an alloy.
(I) How does electrical conductivity and melting point of a metal change when it is converted to its alloy by mixing a small amount of an element in it ? [1]
(II) Name an alloy used for welding two wires together in an electric circuit. Write its major constituents. [1]
(III) (a) What are alloys ? How is 'Brass' (an alloy) prepared ? [2]
Solution
(I) Both electrical conductivity and melting point of an alloy becomes less than that of a pure metal. (Although in some cases the melting point may increases)
(II) Solder
Lead (Pb) & tin (Sn)
(III) (a) An alloy is a homogenous mixture of two or more metals or a metal and a nonmetal.
Brass is an alloy is prepared by mixing Copper and Zinc in definite proportion.