Bio ch02 chemistry basis

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Bio ch02 chemistry basis

  1. 1. KEY CONCEPT All living things are based on atoms and their interactions.
  2. 2. <ul><li>refers to anything that has mass and takes up space. </li></ul><ul><ul><li>92 naturally occurring elements. </li></ul></ul><ul><ul><ul><li>Only six make up 98% body weight of organisms. </li></ul></ul></ul><ul><ul><ul><ul><li>CHNOPS </li></ul></ul></ul></ul><ul><li>Matter </li></ul>
  3. 3. <ul><li>Living and non-living matter consist of atoms of different elements. </li></ul><ul><li>An atom is the smallest basic unit of matter. </li></ul><ul><li>An element is one type of atom. </li></ul>Hydrogen atom (H) Oxygen atom (O) H O
  4. 4. <ul><ul><li>The nucleus has protons and neutrons. </li></ul></ul><ul><ul><li>Electrons are in energy levels outside nucleus. </li></ul></ul><ul><li>An atom has a nucleus and electrons. </li></ul>Oxygen atom (O) Nucleus: 8 protons (+) 8 neutrons outermost energy level: 6 electrons (-) inner energy level: 2 electrons (-)
  5. 5. <ul><li>Atomic Number </li></ul><ul><ul><li>Number of protons in the nucleus </li></ul></ul><ul><li>Atomic mass/ mass number </li></ul><ul><ul><li>Sum of the protons and neutrons in the nucleus </li></ul></ul><ul><li>Isotopes </li></ul><ul><ul><li>Atom of the same element having the same atomic number but different mass number due to number of neutrons </li></ul></ul>
  6. 7. <ul><ul><li>water (H 2 O) </li></ul></ul><ul><li>Elements- 92 naturally occurring and 6 found in living things </li></ul><ul><li>A compound is made of atoms of different elements bonded together. </li></ul>O H H _ + +
  7. 8. <ul><ul><li>carbon dioxide (CO 2 ) </li></ul></ul><ul><li>A compound is made of atoms of different elements bonded together. </li></ul><ul><ul><li>water (H 2 O) </li></ul></ul>
  8. 9. <ul><ul><li>many other carbon-based compounds in living things </li></ul></ul><ul><li>A compound is made of atoms of different elements bonded together. </li></ul><ul><ul><li>water (H 2 O) </li></ul></ul><ul><ul><li>carbon dioxide (CO 2 ) </li></ul></ul>
  9. 10. <ul><li>Ions form when atoms gain or lose electrons. </li></ul><ul><li>An ion is an atom that has gained or lost one or more electrons. </li></ul><ul><ul><li>positive ions </li></ul></ul><ul><ul><li>negative ions </li></ul></ul><ul><li>Ionic bonds form between oppositely charged ions. </li></ul>Sodium atom (Na) Chlorine atom (CI) Sodium ion (Na + ) Chloride ion (CI - ) Na loses an electron to CI ionic bond gained electron
  10. 11. <ul><li>Atoms share pairs of electrons in covalent bonds. </li></ul><ul><li>A covalent bond forms when atoms share a pair of electrons. </li></ul><ul><ul><li>multiple covalent bonds </li></ul></ul><ul><ul><li>diatomic molecules </li></ul></ul>covalent bonds Oxygen atom (O) Carbon atom (C) Oxygen atom (O) Carbon dioxide (CO 2 )
  11. 12. KEY CONCEPT Water’s unique properties allow life to exist on Earth.
  12. 13. <ul><li>Life depends on hydrogen bonds in water. </li></ul><ul><li>Water is a polar molecule. </li></ul><ul><ul><li>Polar molecules have slightly charged regions. </li></ul></ul><ul><ul><li>Nonpolar molecules do not have charged regions. </li></ul></ul><ul><ul><li>Hydrogen bonds form between slightly positive    hydrogen atoms and slightly negative atoms. </li></ul></ul>O H H _ + +
  13. 14. O H H _ + + O H H _ + + O H H _ + + O H H _ + +
  14. 15. <ul><li>Hydrogen bonds are responsible for important properties of water. </li></ul><ul><li>Properties of Water </li></ul><ul><ul><li>High heat capacity </li></ul></ul><ul><ul><li>Large number of hydrogen bonds absorb heat without a large change in temperature. </li></ul></ul>
  15. 16. <ul><li>Properties of Water </li></ul><ul><li>High Heat of Vaporization </li></ul><ul><ul><li>Large number of hydrogen bonds must be broken to evaporate water. </li></ul></ul><ul><li>Universal Solvent </li></ul><ul><li>Cohesive and Adhesive </li></ul><ul><li>High Surface Tension </li></ul>
  16. 17. <ul><li>Many compounds dissolve in water. </li></ul><ul><li>A solution is formed when one substance dissolves in another. </li></ul><ul><ul><li>A solution is a homogeneous mixture. </li></ul></ul><ul><ul><li>Solvents dissolve other substances. </li></ul></ul><ul><ul><li>Solutes dissolve in a solvent. </li></ul></ul>solution
  17. 18. <ul><li>“ Like dissolves like.” </li></ul><ul><ul><li>Polar solvents dissolve polar solutes. </li></ul></ul><ul><ul><li>Nonpolar solvents dissolve nonpolar solutes. </li></ul></ul><ul><ul><li>Polar substances and nonpolar substances generally remain separate. </li></ul></ul><ul><ul><li>Hydrophilic molecules </li></ul></ul><ul><ul><ul><li>Attract water. </li></ul></ul></ul><ul><ul><li>Hydrophobic molecules </li></ul></ul><ul><ul><ul><li>Cannot attract water. </li></ul></ul></ul>
  18. 19. <ul><li>“ Like dissolves like.” </li></ul>
  19. 20. <ul><li>Some compounds form acids or bases. </li></ul><ul><li>An acid releases a hydrogen ion when it dissolves in water. </li></ul><ul><ul><li>high H + concentration </li></ul></ul><ul><ul><li>pH less than 7 </li></ul></ul>more acidic stomach acid pH between 1 and 3
  20. 21. <ul><li>Frozen water is less dense than liquid water </li></ul><ul><ul><li>Ice acts as an insulator on top of a frozen body of water. </li></ul></ul>
  21. 22. <ul><li>Acids and Bases </li></ul><ul><li>pH </li></ul>
  22. 23. <ul><li>Some compounds form acids or bases. </li></ul><ul><li>An acid releases a hydrogen ion when it dissolves in water. </li></ul><ul><ul><li>high H + concentration </li></ul></ul><ul><ul><li>pH less than 7 </li></ul></ul>more acidic stomach acid pH between 1 and 3
  23. 24. <ul><li>Base </li></ul><ul><ul><li>either removes hydrogen ions (H + ) or release hydroxide ions (OH - ). </li></ul></ul><ul><ul><li>low H + concentration </li></ul></ul><ul><ul><li>pH greater than 7 </li></ul></ul>bile pH between 8 and 9 more basic
  24. 25. <ul><li>A neutral solution has a pH of 7. </li></ul>pure water pH 7

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