Non polar molecules like oils and fats do not dissolve in water but instead stay separate. They do not mix as the non-polar molecule has the electro negativities of the two atoms equal. Dipole- dipole forces are the forces that attract the positive end of a polar molecule to a negative end of another polar molecule. These are the forces that bond the electronegative polar oxygen molecule with the positive polar hydrogen molecule. Dipole-dipole forces account for water being attracted to most substances (adhesion). Hydrogen bonding accounts for water being attracted to other water molecules …show more content…
Why is DO important in water? In lakes, creeks and rivers dissolved oxygen is essential in certain concentrations to enable life for marine organisms. Aquatic life needs dissolved oxygen to respire like land organisms .The temperature of water can affect the amount of DO. A cold flowing creek or river can have up to double the amount of dissolved oxygen as a creek with stagnant warm water. This occurs because when oxygen enters the water by either aeration or photosynthesis the cold water allows the oxygen to be enclosed by the molecule as it is in contraction from cold, whereas when the water is warm or hot, the heat drives the oxygen gas out of the molecule. This occurs when because when the H2O is heated up the molecule is moving a lot more allowing the oxygen to escape. Dissolved oxygen enters the water through the air or as a by-product from plants undergoing photosynthesis. Dissolved oxygen gets into the water from the air when water is moving, where it be waves, rapids or waterfalls. Water can also be aerated un naturally or manmade though things like pumps or damns. The way dissolved oxygen gets into water through photosynthesis is when plants like sea weed and algae which grow half in and out of water photosynthesise, the oxygen output gets sent both above the water into the atmosphere and also in the water. Photosynthesis is the process of light energy from the sun being converted into chemical energy for a