1. C HEMISTRY, W ATER, AND P H Chapter 2

2. T HE BASICS Matter is anything that takes up space and has __________ The fundamental unit of matter is the _______. Atomic theories The most important constituent parts of an atom are Atoms are usually neutral Organization of the atom

3. electron shell electron (negative charge) proton (positive charge) neutron (no charge) nucleus Hydrogen (H)Helium (He)

4. E LEMENTS An element is any substance that cannot be reduced to any simpler set of constituent substances through chemical means. Each element is defined by the number of protons in its nucleus= _______________ Difference between iron and gold? The number of _____________in an atom can vary independently of the number of ________________.

5. A single element can exist in various forms, called ____________, depending on the number of _____________it possesses. Mass number = _____________+ ___________________ _____________________is the average mass number of isotopes for one element.

6. C HEMICAL B ONDING ________________: atoms share one or more electrons ________________: atoms lose and accept electrons from each other Atoms “seek” their ____________energy state. This happens when it has a filled _____________________. Hydrogen and helium need _____ e- to be “full” Most elements need ____ e- to have filled outer shells. A molecule ___________________________________________________ _____________________ Water molecule

7. Atoms of different elements differ in their power to attract electrons= _____________. With this, a molecule can take on a _____________—a difference in electrical charge at one end compared to the other. Covalent chemical bonds can be polar or nonpolar. A _________________________exists when shared electrons are not shared equally among atoms in a molecule Two atoms will undergo a process of ____________________when the electronegativity differences between them are great enough that one atom loses 1 or more electrons to the other.

8. _______: atoms whose number of electrons differs from their number of protons. The charge differences can produce an electrostatic attraction between ions = ______________ When atoms of two or more elements bond together _____________, the result is an ______compound. ____________ bonding links an already covalently bonded hydrogen atom with an electronegative atom.

10. M OLECULAR SHAPE MATTERS The three-dimensional molecular shape is important in biology because it determines the capacity molecules have to bind with one another. Review of molecular models

11. W HY WATER IS SO IMPORTANT IN BIOLOGY Required/generated by many cellular reactions Water is a powerful _____________, with the ability to dissolve more compounds in greater amounts than any other liquid.

12. D ENSITY DIFFERENCES Solid versus liquid densities, important for marine organisms. _________ is less dense than _________. Bodies of water in colder climates do not freeze solid in winter. Allows life to flourish under the ice.

13. S PECIFIC HEAT Water has a great capacity to absorb and retain heat. The oceans act as _____________for the Earth, thus stabilizing Earth’s temperature. Desert Body temperature Inland vs shore

14. C OHESION AND SURFACE TENSION Cohesion: Creates surface tension: water molecules below the surface are equally attracted in all directions to other water molecules. At surface, no attraction to air above, so are pulled down and to the side by other water molecules Important biologically:

15. H YDROPHILIC AND H YDROPHOBIC Hydrophobic: A.k.a. Example: Hydrophilic: A.k.a. Example:

16. A CIDS AND BASES An acid ____________H+ when put in aqueous solution. A base _____________H+ in solution. A base added to an acidic solution makes that solution ________ acidic. An acid added to a basic solution makes that solution ________basic. _________________ can act as either an acid or a base.

17. PHPH pH 7 is _________, pH = 7 is __________ The lower the pH, the more __________the solution; the higher the pH, the more _________the solution 1 pH unit corresponds to a _____________________difference in acidity pH= pOH = buffers http://www.youtube.com/watch?v=TfDVLsBXYcM

19. W HY DO WE CARE ABOUT P H IN BIOLOGY ? Cell membranes Reaction rates Asthma Heart burn/acid reflux Cardiac arrest Acidosis Acid rain