notes properties of water

adhesion and cohesion

adhesion and cohesion water is sticky cohesion- water molecules stick to other water molecules as a result of hydrogen bonding adhesion- water molecules stick to other types of molecules because of water's polarity

water is a very good solvent benefit to organisms

dissolved substances are easier to transport; this allows the movement of nutrients into cells and waste out of cells. many kinds of molecules can move freely in cells, permitting a diverse array of chemical reactions

high heat of vaporization benefit to organisms

evaporation of water cools body surfaces evaporative cooling- the release of heat energy when a liquid changes to a gas

high specific heat benefit to organisms

helps stabilize environmental temperatures (air, land, oceans, lakes) helps stabilize the temperature of organisms

Water expands when it freezes benefit to organisms

lakes and ponds do not freeze solid ice acts like an insulator on a body of water helps aquatic organisms survive through the winter months

transparency benefit to organisms

light reaches chloroplasts in cells of algae and aquatic plants allowing the cells to conduct photosynthesis

adhesion and cohesion benefit to organisms

surface tension- "elastic skin" on the surface of water; created by hydrogen bonding allows: insects to "walk" on water rocks to skip across a pond capillary action-movement of water up a narrow tube or xylem cells (tube-like plant cells) A. cohesion: contributes to the transport of water against gravity in plants as water evaporates form the under side of leaves (transpiration), hydrogen bonding causes evaporating water molecules to tug on neighboring water molecules farther down the vein (xylem cells of the vascular bundle) B. adhesion: stickiness of water molecules to the walls of the xylem cells (tube-like plant cells) helps move water up the plant against the pull of gravity

transparency

transparency light passes through water

Water expands when it freezes

water expands when it freezes water becomes less dense when it freezes ice floats because water is less dense as a solid than as a liquid

high heat of vaporization

water has a high heat of vaporization- amount of heat energy that be absorbed in order for a liquid to evaporate. heat energy is released when water evaporates. a relatively large amount of heat enrgy is needed to change liquid water into water vapor. water absorbs a great deal of heat when it evaporates.

high specific heat

water has a high specific heat (heat capacity) high specific heat(heat capacity)- the amount of heat energy that water gains or loses to change temperature. water does not change temperature easily. water resists changing its temperature; when it does change temperature, it absorbs or loses a relatively large amount of heat for each degree change.

water is a very good solvent

water is a very good solvent water dissolves many substances polarity allows water to dissolve ionic compounds (water pulls the ions in an ionic compound apart) polarity allows water to dissolve polar covalent compounds water cannot dissolve covalent compounds (lipids)- fats,oils,waxes