Lecture 2

Question 1

Ionic Bond

Answer 1

• giving e-

- Ionic bond is stronger for MgCl2 than NaCl because of charge (affects solubility, NaCl is easier to dissolve)

Question 2

Which group give up e- easily?

Answer 2

Group 1 and group 7 wants e-

Question 3

Hydrophilic

Answer 3

• water loving

- polar molecules and ions dissolve readily in water

Question 4

what is water important

Answer 4

• extremely good solvent

Question 5

Hydrophobic

Answer 5

• water hating

- nonpolar molecules do not dissolve in water

Question 6

Hydrophobic interaction

Answer 6

• water forces nonpolar molecules tgt coz it minimizes their disruptive effects on the hydrogen bonded water network
• important for protein folding and membrane

Question 7

van der Waals interaction

Answer 7

Nonpolar molecules are also attracted to each other via relatively weak attractions called van der Waals forces (transient dipoles).

Question 8

Bond Energy

Answer 8

• amount of E needed to separate two bonded or interacting atoms under physiological conditions

Question 9

Ionic bond (in biology)

Answer 9

normally very strong but in biology very weak

Question 10

conservation of matter

Answer 10

Energy can neither be created nor destroyed

Question 11

Difference btwn moles and molar

Answer 11

• A mole is the amount of a substance in grams whose weight is equal to its molecular weight
• molar (1M) solution is one mole of a compound dissolved in water to make one liter

Question 12

Acids

Answer 12

• release/donate H+ ions in solution
  if the reaction (dissociation) is complete, it is a strong acid
• COOH is weak because it dissociates partially and reversibly

Question 13

Bases

Answer 13

• accepts H+ in solution (release OH-)
• NaOH ionizes completely to Na+ and OH-. The OH- absorbs H+ to form water. It is a strong base.
• amino group (NH2)
  weak base

Question 14

pH

Answer 14

the negative logarithm of the H+ concentration in moles/liter