FINAL EXAM CHAPTER 2 water

Question 1

What is a Hydrogen Bond?

Answer 1

An electrostatic attraction between polarized molecules containing O-H, N-H, or F-H.

Question 2

When are H bonds the strongest ?

Answer 2

When the bond is linear

Question 3

How is melting of ice and dissolving of salt crystals entropy driven ?

Answer 3

Because the entropy increases whenever heat flows from a hot object to a cold object

Question 4

How does Hydrophobic effect work in the separation of oil and water ?

Answer 4

1. When the oil enters the water, hydrocarbon vdW interactions are broken
2. Water H-bonds are broken
3. New water H-bonds are formed in an organized “cage” around the hydrocarbon. this makes the best out of the vdW interactions between the hydrocarbon and water and it makes the best out of the H-bonding among the water molecules

4.But the entropy of water is reduced, disfavoring dissolution of hydrocarbons in water.

Ultimately you make the water more ordered when you force oil into the water.

Question 5

Define Amphipathic

Answer 5

Molecules that contain both polar and non-polar groups

Question 6

What is a micelle that the detergent forms ?

Answer 6

-When hydrocarbons interact with each other via vdW interactions to form a hydrophobic core and hydrophilic groups associate with water

Question 7

What are some important H bond donors and acceptors?

Answer 7

-Oxygen is a H bond acceptor
-H is a H bond donor

Question 8

For a strong acid how much will it dissociate in water and what will the pH be after?

Answer 8

It will completely dissociate and the pH is 1

Question 9

For a strong base how much will it dissociate in water and what will the pH be ?

Answer 9

Complete dissociation happens and the pH is 14

Question 10

What do titration curves indicate?

Answer 10

The pH values of different mixtures of a weak acid and its conjugate base.