This lab shows the temperature change when alkane and alcohol substances are evaporated. The endothermic process, evaporation, occurs when a substance changes from the liquid to the gas phase. The magnitude of the temperature change can be predicted by studying the intermolecular forces of attraction of the alkanes and alcohols used. All substances used contain dipole dipole forces, but the alcohols used contain hydrogen bonding. Hydrogen bonding occurs when hydrogen atokms bond to highlyelectronegative atoms(nitrogen, oxygen, and fluorine). These bonds are stronger because of the great polarity of the bond and the close approach of the dipoles. The substances with higher intermolecular forces should require more energy to change to a gas. Therefore the higher the intermolecular forces the greater the temperature decrease will be.