Boiling points essays

Boiling points essays Boiling Points and Intermolecular Forces Introduction: Intermolecular force is the force of attraction and repulsion between molecules. They are much weaker than covalent bonds. When boiling a liquid to form a gas, the intermolecular forces are broken not the covalent bonds. A molecular compound that has strong Van der Waals forces will also have a higher boiling point since more energy is required to break the intermolecular bonds. (Notes) Purpose: To test the theory and rules for London and dipole-dipole forces. Question: What trend in boiling points of the hydrogen compounds of elements in groups 14-17? Hypothesis/Prediction: According to dipole-dipole attractions attractive forces are between polar molecules which have higher electronegetivity difference. And only H2O and HF are the polar molecules in group 16 and 17 which means they have the chances of larger dipole moments in the molecules with greater attraction between molecules. Since we know that the strength of the London forces depends on the number of electrons and boiling point increases as the number of electrons increases. And as we see in the groups in each group the number of electrons increases and also the same one repeats itself, but some molecules in it are also polar like HF and H2O. And so when a polar molecule that has the same number of electrons as a non- polar molecule will have higher boiling points due to dipole- dipole forces. And thus it is predicted that the boiling point increases as the of electrons increases in each group. c) The trend in boiling points of the hydrogen compounds of elements in groups 14-17 is that as the total number of electrons increases in the same group and boiling point also increases and also as the group increases the boiling point also increases as they are all non- polar and their number of electrons also increase as it goes down the same group. But there are two exceptions in that t ...