Chemical and physical properties of copper
Answer Text: Properties of copper.a. Physical properties- Soft red-brown metal.- Melting point of #1083^oC# and a boiling point of #2595^oC#- Density is #8.92gcm^(-3)# and electrical conductivity is about #5.93 xx 10^(-9) Ώ^(-1)m^(-1)#b. Chemical properties(i). It does not react with cold water or steam.(ii). Heating in air- When heated in air it forms a black layer of copper (II) oxide on its surface.- Finely divided copper burns with a blue flame.Equation:#2Cu(s) + O_2(g) to 2CuO(s)#(Red brown) (Black)(iii). Reaction with chlorine- Cu reacts with chlorine in presence of heat to form green copper (II) chloride.Equation:#Cu(s) + Cl_2(g) to CuCl_2(s)#(iv). Reaction with Acids.- Copper does not react with dilute hydrochloric, nitric and sulphuric acids.- However it reacts with 50% Nitric acid, concentrated Nitric acid and concentrated sulphuric acid.-With 50% Nitric (V) acid- Copper reduces the nitric acid to nitrogen monoxide.Equation;#3Cu(s) + 8HNO_3(l) to 3Cu(NO_3)_2 (aq) + 4H_2O(l) + 2NO(g)#;-With concentrated Nitric (V) acid- Copper reduces the acid to brown nitrogen (IV) oxide/Nitrogen dioxide gas.Equation:#Cu(s) + 4HNO_3(l) to Cu (NO_3)_2(aq) + 2H_2O(l) + 2NO_2(g)#-With concentrated sulphuric acid.-The sulphuric acid is reduced to sulphur (IV) oxide.Equation:#Cu(s) + 2H_2SO_4(aq) to CuSO_4 (aq) + 2H_2O(l) + SO_2 (g)#
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