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Chemistry of Life

Chemistry of Life. Chapter 2.1. C 6 H 12 O 6 + 6O 2  CO 2 + H 2 O. What elements are represented? What compounds are represented?. How many atoms of each element are represented? Is it balanced? Which scientific law do balanced chemical equations enforce?.

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Chemistry of Life

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  1. Chemistry of Life Chapter 2.1

  2. C6H12O6 + 6O2 CO2 + H2O • What elements are represented? • What compounds are represented?

  3. How many atoms of each element are represented? • Is it balanced? • Which scientific law do balanced chemical equations enforce?

  4. Atoms – The basic unit of matter. Composed of: • Protons – positively charged particles in the nucleus of the atom

  5. Neutrons – particles with mass that have no charge; found in the nucleus of the atom

  6. Electrons – negatively charged particles moving around the nucleus in orbits.

  7. Atoms with equal numbers of protons and electrons are “neutral”

  8. Atoms with uneven numbers of electrons and protons = ion

  9. Atoms with more protons than electrons = cation (positive charge)

  10. Atoms with more electrons than protons = anion (negative charge)

  11. Elements – What is an Element? • One or more atoms • Cannot be broken down or split

  12. Represented by a one or two letter symbol ex. Na (sodium) C (carbon)

  13. Atomic number = number of protons of an element.

  14. Atomic weight = number of protons plus number of neutrons. Ex: Carbon has 6 protons and 6 neutrons; atomic weight is 12

  15. Look at Carbon – C • What is its atomic mass? • Can we tell how many electrons it has? • How? (hint – look at its atomic number)

  16. Isotope – Atoms of the same element that have different numbers of neutrons. Ex: Carbon can have 6, 7, or 8 neutrons

  17. Radioactive isotope – isotopes with unstable nuclei. Give off radiation

  18. Valence electrons • Those electrons that orbit the outer energy level of an atom. • 1st energy  2 electrons • 2nd energy level  8 electrons

  19. Filled make the element more stable • Unfilled energy levels make the element more reactive with other elements.

  20. Compound – substance formed by the chemical combination of 2 or more elements. Ex: H2O, NaCl, HCl.

  21. Compound usually has different properties than the elements it is composed of

  22. Ex: H2O is a liquid composed of gaseous hydrogen and gaseous oxygen.

  23. Chemical bonds – forces that hold elements of a compound together.

  24. Forces are created by the interaction of each of the element’s valence electrons

  25. Ionic Bond – formed when one or more electrons are transferred from one atom to another.

  26. Ex: Sodium (Na) donates one electron to Chlorine (Cl) to form an ionic bond and make sodium chloride (NaCl – table salt)

  27. Covalent Bond – formed when one or more electrons are shared between elements. This type of bond between elements creates a molecule. Ex: H2O

  28. H H O

  29. Properties of Water • A common molecule with unique characteristics:

  30. Polar – due to the way the hydrogen atoms are arranged around the oxygen atom, water molecules have a (+) end and a (-) end = polar.

  31. H H O

  32. This electrical orientation causes water to be attracted to other charged elements and form hydration spheres around them. This keeps the elements from combining with other charged elements.

  33. Ex: salt placed in water dissolves. In other words, the sodium separates from chlorine & water molecules keep them apart. Water helps keep things dissolved = universal solvent

  34. Has a high heat capacity and heat of vaporization – water absorbs, transports, and releases a great deal of heat without changing its state (ice to water to vapor).

  35. That’s why, on a hot day, you just perspire and not evaporate. The water in your body stays liquid (and not turn into a vapor) while it is carrying the heat to the surface of your skin.

  36. Cohesive - sticks to itself; ex: beading water

  37. Adhesive - sticks to other things

  38. Highly reactive – virtually no chemical reactions occur in living systems without the presence of water

  39. It’s the major component of body lubricants (mucus), protective cushions (amniotic fluid and cerebrospinal fluid), and transport mediums (blood)

  40. Salts • In living systems, salts are compounds that dissolve in water and become electrolytes. Electrolytes conduct electricity in the body. Ex: Na, Ca, K, Cl are the major electrolytes. Gatorade has a concentration of these in it.

  41. ACIDS • Compounds that give off hydrogen ions (H+)in solution. Acids read below 7 on the pH scale. The more H+ given off, the lower the number on the pH scale.

  42. Bases • Compounds that give off hydroxide ions (OH-) in solution. Bases read above 7 on the pH scale. The more OH- given off, the higher the pH.

  43. BiochemistryThe Macromolecules of Life Chapter 2.3

  44. Organic Chemistry • The study of all compounds that have bonds between carbon atoms.

  45. Importance of Carbon • Carbon has 4 valence electrons • It tends to form covalent bonds with other carbon atoms

  46. In doing so, carbon can form a variety of shapes…

  47. …chains…

  48. …rings…

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