States of Matter Flashcards
Cohesion and adhesion are manifestations of_____ bonding.
Intermolecular
A system is more stable at what point
When the repulsive and attractive forces are in equilibrium
What governs The balance of forces between two molecules
governed by the negatively charged electron clouds of the molecules.
relates to NON IONIC interaction between molecules
Van Der Waal forces
Give eg of PERMANENT van der wall dipoles
Keesom forces(dipole-dipole) eg. Peptide bonds and HCl intermolecular bonds
What are Debye forces
Induced dipole interactions
Eg. Condensation of non polar gas to for liquids or solids
Relationship between potential energy and distance btn molecules
Potential energy is inversely proportional to the distance of separation raised to the power 6
P.E=k 1/d^6
What interaction shows the ability of a permanent dipole to polarise a neighbouring non polar molecule (which are easily polarisable)
Debye forces or dipole induced dipole.
What are London forces and eg
induced dipole induced dipole attraction
two neighbouring non polar neutral molecules induce partial charge distribution
Eg. conceptualise aliphatic chains in the lipid core of a biologic membrane
Found in Noble gases, diatoms ( O2, H2,N2) and others- Ch4
What interactions account partly for the solubility of ionic crystalline structure in water
Ion dipole interactions
Eg, NaCl and Water
cation Na+ attracts the relatively charged negative oxygen and the anion Cl- attracts the hydrogen atoms of the dipolar water molecules.
interaction that involves charged moieties.
Ion ion interactions or ionic bonds
Weaker ion-ion interactions in salt forms are eg of what interaction
Ion ion interaction
The interaction of a hydrochloride salt of a drug and
salt bridge between counter ions in protein molecules exhibit what interactions
i) Ion ion interaction that is intermolecular
ii) intermolecular ion ion
What properties of pharmaceutical agents does the strength of ion ion interaction have profound effect
pka, pH, solubility
Interaction between a molecule containing hydrogen and a strong electronegative atom (F, O, N)
H bonding
Who discovered H bonds
latimer and Rudebush in 1920
Hydrogen bonds can exist between alcohol molecules, carboxylic acids, aldehydes, esters and polypeptides
T or F
True
solids with high vapour pressure upon heating undergo?
Sublimation
What are ideal gases
- No molecular interaction exist between molecules
2. Collisions perfectly elastic
Boyle’s law
P α 1/v, PV =k
Gay lussac and Charles Law
V α T, V =Kt
Combined gas law
P1V1/T1= P2V2/T2
Change Celcius to Kelvin
Kelvin = Celsius + 273.15.
general ideal gas law
PV = nRT …… 5
Why is the general ideal gas law called equation of state of an ideal gas
because it relates pressure, volume and temperature of a given mass of gas
How do you find the molecular weight of a gas with the ideal gas law
n = m/M, replacing n in the formula PV = nRT = mRT/M M = mRT/PV
Equation for real gas
Page 23
What is critical temperature
temperature when exceeded no amount of pressure can cause the gas to liquify.
What is critical pressure
The pressure required to liquify a gas at the critical temperature
What is highest vapour pressure liquid can have.
Critical pressure
What is the critical temp and pressure of water and helium
Critical temp for water 647K at critical pressure of 218atm,
that of Helium is 5.5k, 2.26atm
the gas phase of substance that is normally liquid at room temperature
Vapor
What variable affects vapor pressure
Temperature only
As T increases Vo increases
When vapour pressure is equal to atmospheric pressure what happens
, there is boiling.
State the Clausius- Claypeyron equation
log 𝑃2 /P1= ∆𝐻𝑣 𝑇2−𝑇1/
2.303𝑅𝑇1𝑇2
Hv is the molar heat of vaporization, that is, the heat absorbed by 1 mole of liquid when it passes into the vapor state.
Solids are incompressible
T or F
True
Morphology of crystalline form of a solid is called____
crystal habit
What are the 6 crystal systems
Cubic – sodium chloride
Tetragonal – urea
Hexagonal – iodoform
Rhombic – iodine Monoclinic – sucrose Triclinic – Boric acid
How does carbon show polymorphism
diamond in a cubic (tetrahedral lattice arrangement)
Graphite in sheet of a hexagonal lattice
When change from one polymorphic form to the other is reversible , the compound is called___
enantiotropic
If the change of one polymorphic form to another is just in one direction it is called –.
monotropic
Characteristics of a stable polymorphic form of a solid and metastable( unstable)
Stable polymorph represents the lowest energy state, has highest melting point and least aqueous solubility.
Metastable form represent the higher energy state, have lower melting point and high aqueous solubility
How do metastable form convert to stable
Metastable form converts to the stable form due to their higher energy state.
What polymorphic form shows better bioavailability and therefore preferred in formulations.
Metastable
What are solvates
solvent traces in the crystal lattice formed when crystallization occurs.
It forms part of the crystal lattice and affects its properties
What are amorphous solids
They differ from crystalline solids in that they tend to flow when subjected to sufficient pressure over a period of time, and they do not have definite melting points.
Give an eg of how a drug being amorphous or crystalline affects its therapeutic activity.
crystalline form of the antibiotic novobiocin acid is poorly absorbed and has no activity, whereas the amorphous form is readily absorbed and therapeutically active. This is due to the differences in the rate of dissolution
