Lecture 3 Flashcards
What are the strengths of the four bonds from strongest to weakest?
Covalent > Ionic > Hydrogen bond > Van der Waals
What are the three Non-covalent interactions?
- Ionic interactions
- Hydrogen bonds
- Van der Waals
Why are H-bonds and Van der Waals still significant despite have a small strength?
Because they are so numerous they have an impact
Which atoms have the highest e- affinities?
O > N > S > C > H
Which atoms can hydrogen bond with to form a dipole?
- H - S
- H - N
- H - O
Why is C H not a hydrogen bond donor?
Because even though C is more electronegative than H it is not strong enough to form a dipole
What must an acceptor in a hydrogen bond have?
An electron pair in a hybridized orbital
What increases water solubility of molecules?
Increased numbers of potential hydrogen bonding groups
How many h-bonds can hydroxyl groups form?
Three; One as a donor two as an acceptor
What does a non-polar molecule not have the ability to form?
H-bond interactions
What happens when a non-polar molecule is in the vicinity of water?
Water tends to form more hydrogen bonds with each other since it is unable to form H-bonds with other molecules and forms an ordered layer of water molecules
How is the entropy of water affect when a non-polar molecule is around water?
Because water forms many h-bonds with each other its entropy goes down because there is less disorder
What is the Hydrophobic effect?
When non-polar molecules go into an aqueous environment, the non-polar compounds tend to associate with each other to reduce the amount of surface area exposed so that the entropy of water goes up because water is forming less h-bonds with each other
What entropy is favoured in the hydrophobic effect?
Higher entropy due to less hydrogen bond forming and more disorder
What is the hydrophobic effect mainly about?
It about water not wanting to interact with non-polar groups and pushing those groups together so that water can maintain its disordered state as much as possible
