Molecular Forces Flashcards
What is the difference between intramolecular and intermolecular forces?
Intramolecular forces:
* Force within the molecule of a compound.
* Decides shape and polarity.
Intermolecular forces:
* Force between molecules of a compound.
* Decides, b.p, f.p and solubility.
What is solubility?
The maximum amount of solute that can be dissolved into a given amount of solvent at a particular temperature.
What leads to insolubility?
Large differences in polarity
What are the properties of water?
- The most important property is the ability to form hydrogen bonds with themselves and other molecules.
- High specific heat.
- Large enthalpy of vaporization.
- Important solvent that dissolves ions and polar molecules.
- Organises non-polar solutes- Hydrophobic solutes aggregate and assume different shapes in water.
- Solid water is less dense than liquid water.
- Water forms ions.
What is specific heat?
Specific heat is the amount of heat required to raise the temperature of a 1g of substance by 1 deg celsius.
What is the consequence of large heat of vaprization of water?
Water cools the surface from which it evaporates.
Why is ice less than water?
Crystallisation of water cause the formation of a lot of empty spaces, making it less dense.
What is a hygdrogen bond?
Intermolecular forces of attraction between molecules where hydrogen is attached to a more electronegative atom such as N, O or F.
Why are hydrogen bonds formed?
Due to the large difference in electronegativity of H and the other atom, they acquire high partial positive and partial negative charge respectively.
Hence, there is electrostatic attraction between the two charged particles of different molecules.
What are the properties of hydrogen bond?
- Individually, it is a weak bond but collectively, it is strong.
- The boiling point of compouns with higher electronegative atom is more.
Why is the b.p of H2O> NH3?
- O is more electronegative than N.
- O has two lone pairs, giving two potential sites for the formation of H-bond. This forms a complex network of attarcive forces.
Why is the b.p. of H2O> HF?
HF has less hdrogens.
What is the importance of H-bond?
Stabilises the protein and DNA structure in our biological systems.
What is coordinate bond?
- It is the bond formed between two atoms when one atom donates a pair of unbound electrons and the other atom accepts it.
- It forms between metals and non-metals.
- The electrons are accpeted by the metals in their vacant orbitals.
What is the difference between ionic bond and coordinate bond?
Ionic bond is formed between two ions.
