Question

1.List three main factors which affect melting point of pure sample :

B) select two factor and explain your answer

Answer 1

Main factors which affect the melting point of a pure sample (No impurity) are Molecular composition, the Molecular force of attraction, Shape of Molecules and Size of Molecules

Molecular composition

A material has a higher melting point if molecules are tightly packed together, than a substance with molecules that do not pack well. Covalent bonds are also effects melting points. material with giant covalent structures has extremely high melting points because several strong covalent bonds must be broken before they can melt.

Molecular Size

Molecular size affects the melting point. smaller molecules melt at lower temperatures than larger molecules. For example, the melting point of ethanol is -114.1 ^oC while the melting point of the larger ethyl cellulose molecule is 151 ^oC