Water Properties (6.5) Part 1 7th Grade Life Science Water Properties (6.5) Part 1

Earth 2/3rds covered by water

Organisms are mostly water

Polar covalent bonding of water molecule See how each end(pole) has an electrical charge?

Hydrogen bonding between water molecules See the central molecule bonding to the 4 outside molecules?

Cohesion

Water needs to get to the leaves for Photosynthesis Water needs to get to the leaves for Photosynthesis. Cohesion of water helps.

Adhesion See the water molecules binding to the Na+ or Cl- Adhesion See the water molecules binding to the Na+ or Cl-? Which atoms of water are are attracted to the Na+? How about to the Cl-?

Surface Tension

Earth and Temperature

States of Water on Earth Solid, Liquid, and Gas

All four Hydrogen bonds have to break at the same time to allow water to evaporate in a gas. That requires a lot of Energy.

Ice versus Water It is about molecule movement.

Evaporative Cooling

Expansion of water as it freezes Look at the distance between water molecules. Which one looks more dense as a whole?

Water Floating

Life below the water

Pre-AP Biology Water Properties Part 2

Water dissolving “pulling apart” the salt See the water forming “shells” around the Na+ and Cl-? Which molecule is the solvent? The solute?

Hydrophobic Water “fearing” substances See how they do not interact/mix?

Salt is hydrophilic in water.

Dissociation of Water

pH scale The “H” in pH is for Hydrogen Measuring the concentration of Hydrogen ions (H+) within a substance

Acid Rain Source Burning fossil fuels such as oil or gas

The effect of acid rain on plants See the dead trees?

Acid Rain and Concrete