Chemistry of Life UEQ: How do the properties and structures of materials determine their uses? What determines the type and extent of a chemical reaction? 1.What is an atom? 2.What are isotopes? What makes an isotope radioactive? 3.What are the different types of chemical bonds? 4.What is the difference between an acid and a base? 1.Why is water considered a polar molecule? 2.What properties result from water’s polarity? General Chemistry Water Organic Molecules 1.What are organic polymers? 2.How are organic polymers made? 3.What is an enzyme? 4.What role does each play in homeostasis?

Warm UP! 1.What is an atom? 2.Name the components of an atom. 3.What is a valence electron?

Hydrogen bonds are weak bonds. This means they can break apart easily. Molecules with H and either N, O, or F can form hydrogen bonds.

Hydrogen bonds For example: a H in one water molecule forms a Hydrogen bond with an O in another water molecule. This bond forms because in H20 the Hydrogen atoms have a partial positive charge which are attracted to partially negatively charged Oxygen atoms in other H20 molecules. Click on water molecules to see demonstration

Why is it unique? The attraction created by hydrogen bonds keeps water liquid over a wider range of temperature than is found for any other molecule its size. The energy required to break multiple hydrogen bonds requires a large amount of energy to convert to liquid water.

Cohesion, Adhesion, and surface tension of water molecules Water is attracted to other water. This is called cohesion. Water can also be attracted to other materials. This is called adhesion. Surface tension is the name we give to the cohesion of water molecules at the surface of a body of water.

Capillary action Surface tension is related to the cohesive properties of water. Capillary action however, is related to the adhesive properties of water. Capillary action is limited by gravity and the size of the straw.

Grab your partner and some pennies we are going to do a quick demonstration