BIOL 1020 Lecture Notes - Lecture 2: Chemical Polarity, Melting Point, Acid Rain

• School: University of Manitoba
• Department: Biological Sciences
• Course: BIOL 1020
• Professor: Michael P.Shaw

Document Summary

Formation of molecules/chemical bonding (covalent and ionic) Properties of water that support life on earth: versatility as solvent, expansion upon freezing, cohesive behaviour, moderation of temperature. Water contains polar covalent bonds: oxygen- stronger attraction for electrons (en) pulls electrons towards it, oxygen in water has a partial negative charge. Hydrogen bonding: attraction between h atom in a polar covalent bond and another en atom. H-bonding in ice is more ordered than in liquid water: Ice is less dense, and has a larger volume. In liquid form waters hydrogen bonds break and form constantly. Presence of solutes decreases the freezing point of a solvent called freezing point depression. Freezing point of seawater lower than freshwater. High concentrations of solutes in some organisms in the winter/ in cold climates can prevent body fluids from freezing: eg. Glycerol concentration in smelt blood (plasma) increases as temperature decreases. Water molecules from hydrogen bonds with other polar molecules and each other.