In: Chemistry
Using the concepts of bond energy and bound length.
1) Why materials usually expand when heated?
2) Why some metals expand more easily than others?
1) The materials genrally made of molecles formed by atoms bonded together.When temprature is increased the vibrational energy of the bond increases depending on the force constant of a bond the bond vibration varies as the bond vibration increses an bond energy also tends to increase and hence lengthning the bond and making the compound to expand.
2) Some metals expand more than others due to differences in the forces between the atoms / molecules. In metals such as iron the forces between the atoms are stronger so it is more difficult for the atoms to move around . In brass the forces are a little weaker so the atoms are free to move about more
Hence increase in temprature increases the bond energy hence making the bonds longer and materials expand.