BIOL111 L2

• What does electronegativity define?

  The tendency of an atom to attract electrons
• What is the shape of a water molecule described in terms of?

  Hybridisation and lone pairs
• What is the significance of hydrogen bonding in water?

  It contributes to water's unique properties
• How many hydrogen atoms are in a water molecule?

  Two
• What type of bonds are formed between hydrogen and oxygen in a water molecule?

  Single polar covalent bonds
• Why does the oxygen atom in a water molecule have a partial negative charge?

  Because oxygen is more electronegative than hydrogen
• What is the bond angle in a water molecule due to lone pair repulsion?

  104.5 degrees
• How does the boiling point of water compare to other molecules?

  Water has a higher boiling point than many other molecules
• What are the effects of hydrogen bonds in water?

  1. Higher boiling point
  2. Higher cohesion
  3. High heat of vaporization
  4. Ice floats due to a more open structure
  5. Higher surface tension
  6. Higher specific heat
  7. Good solvent for polar molecules
  8. Good solvent for ionic compounds
• What is Avogadro's number?

  1. 02 x 10$^{23}$
• How many grams of water are in one mole?

  18 grams
• What does a 1 molar (1M) solution contain?

  1 mole/litre of solution
• What does pH measure?

  The concentration of protons (H$^{+}$) in an aqueous solution
• What is the pH range of a solution?

  1 to 14
• What happens to the pH of a solution as acidity increases?

  The pH decreases
• What is the dissociation constant of water (K$w$)?


  K$w$ = [H$^{+}$][OH$^{-}$] = 10$^{-14}$
• What is the pH of pure water?

  7
• How does the concentration of H$^{+}$ ions relate to pH?


  A solution of pH 3 has [H$^{+}$] of 10$^{-3}$ M
• How does a solution of pH 3 compare to a solution of pH 6?

  A solution of pH 3 is a thousand times more acidic than a solution of pH 6
• What is the relationship between [H$^{+}$] and [OH$^{-}$] in water?


  As [H$^{+}$] increases, [OH$^{-}$] decreases
• What is the significance of the 'Oil Drop Effect' in water?

  It maximizes the number of hydrogen bonds formed by clustering non-polar molecules
• What is the molecular mass of NaOH?

  40 Da
• How many grams of NaOH are needed to make a 1M solution?

  40 grams per litre
• What does the term 'molarity' refer to?

  The concentration of a solution in moles per litre
• What is the relationship between molecular mass and moles?

  1 mole of a substance is equivalent to its molecular mass in grams
• What is the role of water in biological systems?

  Water acts as a solvent and participates in biochemical reactions
• How does water's high specific heat benefit organisms?

  It helps maintain stable temperatures in organisms
• What is the significance of the hydration shell around ions in water?

  It stabilizes ions in solution
• What happens to water molecules near non-polar molecules?

  They cannot satisfy their hydrogen bonding requirements and become less stable
• What is the effect of hydrogen bonding on water's surface tension?

  It increases the surface tension of water
• How does water's high heat of vaporization benefit organisms?

  It allows for effective cooling through processes like sweating
• What is the relationship between temperature and hydrogen bonds in water?

  Heating water breaks hydrogen bonds, while cooling forms them
• What is the significance of the ordered arrangement of molecules on the surface of water?

  It allows water to act like a skin, increasing surface tension
• What is the effect of water's polarity on its solvent properties?

  Water is a good solvent for polar and ionic compounds
• How does the structure of ice differ from liquid water?

  Ice has a more open structure than liquid water
• What is the significance of the temperature at which water is liquid?

  Water remains liquid at room temperature, supporting life
• What is the role of hydrogen bonds in the properties of water?

  Hydrogen bonds contribute to water's unique physical and chemical properties
• What is the importance of studying water in biology?

  Water is essential for biochemical reactions and maintaining life
• How does water's ability to form hydrogen bonds affect its temperature regulation?

  It allows water to absorb and release heat without significant temperature changes
• What is the significance of the molecular mass of water?

  It determines the number of molecules in a given mass of water