Describe the properties of alkenes in terms of addition reactions with: (a) bromine or aqueous bromine (b) hydrogen in the presence of a nickel catalyst (c) steam in the presence of an acid catalyst and draw the structural or displayed formulae of the products

Describe relative atomic mass, ( A_r ), as the average mass of the isotopes of an element compared to 1/12th of the mass of an atom of ( ^{12}C )