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The Nature of Matter

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  1. The Nature of Matter

  2. The Atom • Extremely small – 100 million = 1 centimeter • Subatomic particles • Proton - positive • Electron - negative • Neutron - neutral

  3. Elements • Pure substance that consists entirely of one type of atom

  4. Isotopes • Atoms of same element that differ in the number of neutrons they contain • Radioactive: • Nuclei are unstable • Break down at a constant rate Used for fossil dating

  5. Chemical Compounds • Substance formed by 2 or more elements • Ex. Water H2O, NaCl

  6. Chemical Compounds • A force that joins atoms together is called a chemical bond • Every compound is represented by a chemical formula that identifies the elements in the compound and their proportions • H2O • H2O2

  7. Electron configuration • Electrons are found in orbitals around the nucleus • Follows the octet rule • 1st orbital (or shell) max electrons = 2 • 2nd orbital – max electrons = 8 • 3rd orbital – max electrons = 8

  8. Chemical Bonds • Valence electrons – those electrons available to form bonds (outer most electrons) • Ion – charged particle • Ionic bond – one or more electrons are gained or lost (ex: salt) • Lose electron – become + • Gain electron – become -

  9. Covalent Bonds • Atoms share electrons to fill outer shell • Molecule – atoms joined by covalent bonds • Smallest unit of most compounds

  10. Covalent Bonds • An element becomes stable when its outer electron level is full • Give two examples of molecules formed from covalent bonds: • carbon dioxide • water

  11. Other Bonds • Hydrogen bonds- a weak chemical attraction between polar molecules • Ex: water molecules

  12. Other Bonds • Van der Waals forces- slight attraction between oppositely charged regions of nearby molecules (ex-gecko feet) • Not as strong as ionic or covalent bonds

  13. Water • Water is a major component of cells • Nearly 80% of your body is made of water • What properties of water make it such an important substance for life? • Water stores heat efficiently • Water sticks to itself and other substances

  14. Water • Is a polar molecule • Due to its electrons being shared unequally • The oxygen has a much stronger pull on the electrons than the hydrogens do • We can show this with (+) and (-)

  15. Polar- Magnets

  16. Polar vs Nonpolar • Polar substances mix together (water) • Nonpolar substances mix together (oil) • Polar and nonpolar substances do not mix together (water and oil)

  17. Water- Hydrogen bonding • Due to slight negative and positive charges • Gives water many of its unique properties (cohesion) • Allows it to “stick” together • forms droplets and thin film • Surface tension • Bugs can walk on it

  18. Hydrogen Bonds

  19. Cohesion • Attraction between molecules of the same substance • When like substances stick together • Water to water

  20. Adhesion • Attraction between molecules of different substances • When different substance stick together • Ex- Glass and water- meniscus • Causes some things to get wet

  21. Capillary Action • Water moving up through a small tube • Adhesion- allows the water to stick to the sides of the tube • Cohesion- allows the water molecules to stick together while climbing • Ex: girls going to the bathroom as a group!! • Ex: water going up a plant from the roots

  22. Capillary Action

  23. Heat Capacity • Because of the multiple hydrogen bonds water requires a lot of energy to heat up • Regulates temperature in • Ocean and lakes • Cells • Boiling water • How long does it take? • When can you touch it?

  24. Mixtures • Material composed of two or more elements or compounds that are physically mixed together but not chemically combined • Two types that involve water • Solutions • Suspensions

  25. Solutions • Solute- what is being dissolved (Koolaid powder) • Solvent- what the solute is being dissolved in (water) • Solute + Solvent = Solution (Koolaid)

  26. Water as a Solvent • Water is the universal solvent • Because it is polar it can dissolve • Other polar substances • Ionic compounds • Salts • Sugars • Minerals • Gases • Even other solvents such as alcohol

  27. Water as a Solvent • Saturated Solution- the water can’t dissolve any more solute

  28. Suspension • A mixture of water and non-dissolved material • Some materials do not dissolve when placed in water, but separate into pieces so small that they do not settle out • Ex: blood

  29. pH Scale • pH stands for potential hydrogen, 0-14

  30. pH Scale • Measure the concentration of H+ (hydrogen ions) • Above 7 is basic • 7 is neutral • Below 7 is acidic

  31. Neutral • Has equal numbers of H+ and OH- • Ex: water

  32. Basic • A base is a compound that produces hydroxide (OH–) ions in solution. • Ex: baking soda • Has more OH- than H+ • The closer to 14 the stronger • The closer to 7 the weaker • Usually end in -OH

  33. Acids • An acid is any compound that forms H+ ions in solution. • Ex: orange juice, HCl (stomach acid) • Has more H+ than OH- • The closer to 0 the stronger • The closer to 7 the weaker • Usually begin with H-

  34. Buffers • Keep solutions from becoming two acidic or basic • Weak acids or bases • Essential in maintaining homeostasis • The pH of the fluids within most cells in the human body must generally be kept between 6.5 and 7.5

  35. Buffers

  36. Carbon • Has 4 valence electrons • Forms covalent bonds • Makes up organic compounds • Can bond with • Hydrogen • Oxygen • Phosphorus • Sulfur • Nitrogen

  37. Carbon • Can bond to each other • Single • Double • Triple

  38. Macromolecules • Giant molecules • Made from monomers (single unit) • Polymer- many monomers

  39. Organic Macromolecules • Carbohydrates • Lipids • Proteins • Nucleic Acids

  40. Carbohydrates • Organic compounds made of carbon, hydrogen and oxygen in a proportion of 1:2:1 • The building blocks of carbohydrates are called monosaccharides • Glucose is a major source of energy for cells • Give an example of a food that contains carbohydrates: pasta, bread, potatoes • Structural in plants- cellulose

  41. Carbohydrates • Sugars • End in –ose • Plants store energy • starches

  42. Carbohydrates • Monosaccharide- Single sugar • Glucose, galactose, fructose • Disaccharide- two sugars, table sugar • Polysaccharide- many sugars, glycogen

  43. Lipids • Important part of the structure and functioning of cell membranes • Examples of lipids: waxes, fats, steroids, oils • Lipids that store energy are called fat • Give an example of a food that is a lipid: butter • Natural waterproofing

  44. Saturated vs Unsaturated

  45. Saturated vs. Unsaturated • Saturated • Normally animal based • Solid at room temperature • No double bonds between carbons • Ex- butter • Unsaturated • Normally plant based • Liquid at room temperature • At least one double bond between carbons • Ex- corn oil

  46. Proteins • Made of nitrogen, hydrogen, carbon, and oxygen • Polymers made of monomers called amino acids • 20 amino acids • Peptide bonds link these monomers (type of covalent bond) • Give an example of a food high in protein: meat, fish, eggs, nuts

  47. Functions of Proteins • Enzymes - control the rate of reactions and regulating cell processes • Forming cellular structures • Transporting substances into or out of cells, • Helping to fight disease. • Where is it found? Skin, bones, ligaments, tendons • The most abundant protein in your body is collagen

  48. Levels of Protein Organization • Four levels • Primary- sequence of amino acids (polypeptide) • Secondary- folding or coiling of the polypeptide • Tertiary- 3-d arrangement of polypeptide • Quaternary- made up of more than one polypeptide

  49. Levels of Protein Organization