PHT 121 miu fall 2024 lec 1-2-3

........ molecules move around each other

• solid

• liquid

• gas

particles of ....... are compressible

• solid

• liquid

• gas

crystalline substances have no definite melting points

• True

• false

crystalline Penicillin G (as potassium or sodium salt) are not used for formulating parenteral penicillin G

• true

• false

A single chemical substance existing in more than one crystalline form depending upon the conditions (temp. , solvent , time ) under which crystallization is induced.

• Solubility

• isomorph

• polymorph

It is the boundary between 2 phases, one of them is gas      

• surface

• interface

.................are those which act between molecules of the same phase.

• adhesive forces

• cohesive forces

Liquid droplets tend to assume a spherical shape because........

• At the surface Cohesion is greater than Adhesion

• At the surface Cohesion is less than Adhesion

• At the surface Cohesion is equal to Adhesion

If the force of adhesion between the substance molecules and the water molecules

is greater than

the cohesive force between the substance molecules themselves so.......

• Spread as a film

• Do not spread and form separate lens

Concentration of a certain substance at interface or surface > Conc in bulk.

• negative adsorption

• positive adsorption

• absorption