Ionic bonds are formed between two oppositely charged ions.
C. Hydrogen Bonds: weak bonds between polar molecules. (One example is a water molecule.)
* A hydrogen bond is always represented with a dotted or dashed line.
II. Chemical Reactions
A. Exergonic vs. Endergonic
Endergonic: Energy is added to the product
Exergonic: Energy is released from the substrate
(see the graph from a neighbor's notes)
Activation Energy: amount of energy required to "start" the reaction (if paper is the substrate, and air and ashes are the product, then the match is the activation energy.)
* In our bodies, we have millions of endergonic and exergonic reactions. Ensymes provides the activation energy. An ensyme does not contribute or take away atoms from the reaction, however.
B. Redox Reactions
* Redox is short for Reduction/Oxidation.
Redox Reaction: stripping electrons off of one chemical (the chemical that has been oxidized) and adding them to another (that one is the reduced chemical.)
* One example is photosynthesis.
* It is both an endergnoic and an exergonic reaction.
* the chemical that has reduced is gaining energy, and the chemical that is oxidized is losing energy.
III. Chemistry of Water
Water's properties:
water can stick to other objects as well as itself
Cohesion: the attraction between water molecules (unlike charges attract)
water is polar because of its symmetry
Surface Tension: the surface of a liquid can exhibit strong intermoleculure forces
Adhesion: water sticks to other POLAR molecules
Capillary Action: allows plants to pull water up into plant itself
* water is the best solvent.
* a solution forms when 1 substance dissolves (forms hydrogen bonds) into another.
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