BIO 253 Chapter 3

Card Set Information

BIO 253 Chapter 3
2012-09-15 07:18:55
BI 253

Chapter 3; 9-13-12
Show Answers:

  1. What is an aqueous Solution?
    Solution where water is the solvent
  2. Define cohesion.
    Linking together of molecules, often by hydrogen bonds
  3. What is the solute?
    Substance dissolved in a solution
  4. What is specific heat?
    Amt of heat, absorbed of lost, for 1g of a substance to change temp 1⁰C
  5. What is the hydronium ion?
    • Water molecule that has an extra p⁺ bound to it; H₃O+
    • More commonly H⁺
  6. Describe a hydrogen ion.
    A single proton with a charge of 1+
  7. What is created when water dissociates?
    • Hydroxide ion (OH⁻)
    • Hydrogen Ion (H⁺)
  8. What happens when hydrogen ion is in water?
    It associates w/a H₂O molecule and forms a hydronium ion
  9. Describe a kilocalorie (kcal).
    • 1000 calories
    • Amt heat energy needed to raise 1kg H₂O 1⁰C
  10. What is the heat of vaporization?
    Quantity of heat a liquid must absorb to convert 1g fr liquid to gas
  11. Define Molarity.
    • Measure of solute concentration
    • # of moles of solute / liter of solution
  12. Define hydrophobic.
    Having no affinity for water
  13. What is a solution?
    Liquid that is homogeneous mix of 2 or more substances
  14. Define a hydration shell.
    Sphere of water molecules around a dissolved ion.
  15. What is a buffer?
    • Solution containing a weak acid & it conjugate base
    • Resists radical changes in pH when acids or bases are added
  16. A molecule w/an uneven distribution of charges in different regions of the molecule is a ___ ___.
    Polar Molecule
  17. Define a mole.
    # of grams of a substance that equals its molar weight in daltons & contains Avegadros # of molecules
  18. A calorie is . . . .
    Amt of heat energy needed to raise 1g H₂O 1⁰C.
  19. An acid is what?
    Substance the increases H⁺ concen of a solution
  20. A mixture made up of liquid & particles that remain suspended rather than dissolving is called a ____ ____.
    Colloid Mixture
  21. What is adhesion?
    Clinging of 1 substance to another by means of hydrogen bonds
  22. 2 molecules of H₂O are bonded together by a ____ ____.
    Hydrogen bond
  23. Ice is held in ___ ___ by the orientation of water molecules' ____ ____.
    • Crystalline Structure
    • Hydrogen Bonds
  24. Why does water expand as it freezes?
    b/c hydrogen bonds increase space water molecules take up in their solid state
  25. What is the specific heat of water and what does it define?
    • 1cal/g/⁰C
    • Defines the calorie (4.187 j)
  26. What is the approx heat of vaporization of water?
    540 cal/gram
  27. What is an aqueous solution?
    One where water is the solvent
  28. What does a strong acid do in water?
    Completely & irreversibly dissociates
  29. What a weak acid do in water?
    Only partially dissociates and dissociation can be reversed
  30. Describe a base.
    Accepts H⁺ ions (protons)
  31. How does a strong base act in H₂O?
    Completely & irreversibly dissociates
  32. How does a weak base act in H₂O?
    Partially dissociates & dissociation can be reversed
  33. What is a joule (J)?
    A unit of energy: 1 J = 0.239 cal: 1 cal = 4.184 J
  34. A hydrophilic substance is one that. . . .
    Has a affinity for water
  35. Define pH.
    Measure of H⁺ concentration = to -Log [H⁺] & ranging in value 0 to 14
  36. Surface tension is defined as?
    Measure of how difficult it is to stretch or break the surface of a liquid
  37. What is temperature?
    Measure of intensity of heat in degrees; reflecting avg kinetic energy of molecules
  38. Evaporative cooling is described as?
    Process in which the surface of an object becomes cooler during evaporation
  39. Define heat.
    Total amt of kinetic energy due to random motion of atoms or molecules in a body of matter
  40. The molecular mass is the . . . .
    Sum of the masses of all the atoms in a molecule
  41. Kinetic energy is a measure of what?
    Energy assoc w/relative motion of objects
  42. Ocean acidification is described as. . . .
    Decreasing pH of ocean water due to absorption of excess CO₂ fr burning of fossil fuels
  43. The hydroxide ion is what?
    • A water molecule that has lost a p⁺
    • symbol = OH⁻
  44. Describe acid precipitation.
    Rain, snow or fog that is more acidic than pH 5.2
  45. Polar covalent bonds are described as?
    Bond between atoms w/diff electronegativity. Shared e⁻ are pulled closer to more electronegative atom making it slightly neg & other slightly pos
  46. What is a solvent?
    • Dissolving agent in a solution
    • Water is universal solvent