MP, BP, Miscibility & Solubility - Structure & Properties (2.3) Flashcards
When simple covalent molecules melt and boil, what is broken?
Intermolecular Forces
London Forces are strongest in:
Molecules with more electrons and larger surface area contact.
Dipole- dipole interaction are strongest in:
Molecules with large dipoles (large electronegativity differences).
Hydrogen Bonds are strongest in:
Molecules with fluorine as the hydrogen acceptor ( highest electronegativity).
Do more electronegative elements have a higher boiling points? Why?
Yes, because the intermolecular forces are stronger and more energy is required to break the forces between the molecules.
When two liquids mix completely together they are:
Miscible
When liquids form two phases they are:
immiscible
Miscible substances are stronger than immiscible substances. True or False?
True - as the system will do what gives the strongest total molecular forces.
Why are miscible substances stronger than immiscible substances?
The intermolecular forces in the mixture are similar in strength, so mixing is favoured.
Solubility is…
measure of how much of a solute dissolves in a solvent. (like dissolves like).
Ionic Solids are soluble because…
They dissociate in water.
The ions in ionic solids are soluble because…
they form strong ion-dipole interaction with water.
Covalent molecules are not very soluble in water, but rather in…
organic solvents
Why are drugs often administered as salts rather than their parent drug?
Salt is an ionic substance and would therefore dissolve better in water/ blood/ in the human body and weaker forces would form between the parent molecule and water.
Why are drugs often administered as salts rather than their parent drug?
Salt is an ionic substance and would therefore dissolve better in water/ blood/ in the human body and weaker forces would form between the parent molecule and water.
