Chemistry of Life Properties Of Water

Properties of water: cohesion, adhesion, heat capacity, solvent Objective I can explain how the properties of water contribute to the maintenance of cells and living organisms. Properties of water: cohesion, adhesion, heat capacity, solvent

Name the 4 macromolecules and their functions. Starter Name the 4 macromolecules and their functions.

Make 5 observations about the characteristics or behavior that water exhibits.

Water Rotation Lab

Importance of Water Water makes up 70-95% of most living organisms All the chemical reaction s of life are carried out in water-based fluids

Water is a Polar Molecule H2O – the oxygen atom shares its electrons with hydrogen in an unequal manner Polarity: a separation of charge into distinct + and – regions. The slight + charge of a hydrogen atom is drawn to the slight – charge of the oxygen atom. This type of interaction is called a hydrogen bond.

Hydrogen Bonds Weak bonds Hydrogen bonds are important to organisms because they help to hold large molecules together Hydrogen bonds give water its unique properties

Properties of Water Cohesion Adhesion Heat Capacity Solvent Properties

Cohesion Cohesion: molecules of the same substance resist being separated from one another Water molecules stick to other water molecules Water molecules tend to clump together – water drops, surface tension

Adhesion Adhesion: molecules of 1 kind are attracted to molecules of another kind Allows water to cling to the sides of a container that hold it Responsible for capillary action

Heat Capacity Heat Capacity: the amount of heat needed to raise the temperature by 1 degree Water is able to absorb a large amount of heat before changing phase or boiling – temperature stability Water is like an insulator, it helps maintain a steady environment when conditions fluctuate

Heat of Vaporization Heat of vaporization: the amount of energy required for a substance to change from a liquid to a gas As water molecules evaporate, the surface they evaporate from gets cooler, a process called evaporative cooling. In living organisms, the evaporation of sweat cools the body to maintain a steady temperature.

Solvent Solvent: liquid that can dissolve other substance Solute: a dissolved substance Solution: a mixture of solute and solvent

Universal Solvent Ionic solids such as NaCl dissolve in water because waters hydrogen bonds are stronger than the ionic bonds. Water molecules tug the ions apart and surround each one.

Recap Video: Properties of Water

Properties of water: cohesion, adhesion, heat capacity, solvent Objective I can explain how the properties of water contribute to the maintenance of cells and living organisms. Properties of water: cohesion, adhesion, heat capacity, solvent