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level: Level 1 of GENERAL IDEA

Questions and Answers List

level questions: Level 1 of GENERAL IDEA

Question	Answer
Defined as the fluid for which the relationship between shear stress and rate shear is not constant	Non - Newtonian system
1 Examples of Newtonian Fluid 2 EXAMPLES OF NON NEWTONIAN FLUID	1 Castor oil Chloroform Ethanol Olive oil Water 2 Emulsion Suspension Ointment
Types of Non - Newtonian	1. Plastic flow 2. Pseudo - plastic flow 3. Dilatant flow
Also known as consistency curves or flow curves	Rheogram
Formed when the active molecules saturate the surface of the water	Micelles
1 Potential located at the sheer plane 2 The potential at the solid surface due to the potential determining ion, is the electrothermodynamic (Nernst) potential, E	1 Electrokinetic or Zeta Potential 2 Nernst and Zeta Potentials
Substance that lowers the surface tension of the medium in which it is dissolved	Surface Active Agent
Measuring Surface and Interfacial Tension METHODS	1 Du Nouy Ring Method (Pierre Lecomte du Nouy) 2 Capillary Rise Method
The narrower the capillary tube, the ___ the water level	higher
Methods Used in Particle Size Determination	1. Optical Microscopy 2 Sieve Analysis 3 Sedimentation
Apparatus used in sedimentation	Andreasen apparatus
Height of voltage pulse is proportional to the volume of particle	.
1 Reduction of viscosity with the increasing rate of shear and example 2 Increase viscosity or resistance to flow with increasing rate of shear and example	1 Pseudo - plastic or “Shear - thinning” ex. tragacanth, sodium alginate, methylcellulose and Na CMC, toothpaste 2 Dilatant Flow or “Shear - Thickening” ex. deflocculated suspension
Defined as rheological phenomenon in which the flowing behavior of the material occurs after the applied stress reaches a critical value or yield value and then behaves as Newtonian flow	Plastic flow or Bingham Bodies Ex. Flocculated suspension Ointment Paste Gel
“An isothermal and comparatively slow recovery, on standing of a material, of a consistency lost through shearing”	Thixotropy
A phenomenon in which a solid forms a gel more readily when gently shaken or otherwise sheared than when allowed to form the gel while the material is kept at rest	Rheopexy
Greater thixotropy, the __ rate of settling	lower
In Dispersed System 1 Particulate Matter 2 Dispersing Medium	1 Dispersed Phase 2 Continuous Phase
Homogeneous, non crystalline substance consisting of large molecules or ultramicroscopic particles of one substance dispersed through a second substance	Colloids
1 “Solvent - loving” 2 “Solvent - hating”	1 Lyophilic Colloids 2 Lyophobic Colloids
When a strong beam of light is passed through a colloidal solution, the path of light is illuminated (a visible cone formed)	Faraday - Tyndall Effect
Depend on Tyndall Effect Used to give information about particle size and shape and for determination of molecular weight of colloids	Light Scattering
Zig - zag movement of colloidal particles continuously and randomly	Brownian Motion
Diffusion is governed by what law?	Ficks Law
Semipermeable cellophane membrane prevent the passage of colloidal particles, yet allow the passage of small molecules or electrolytes	Dialysis
Some solvents which themselves have high viscosity are used as co - solvents to enhance the viscosity of dispersion medium	Co - solvents
Formation of light, fluffy groups of particles held together by weak Van der Waals forces	Flocculation
Difficult to disperse solid particles in a liquid vehicle due to the layer of adsorbed air on the surface	Wetting Agents
Movement of particles (diffusion flux) from high to low concentration is directly proportional to the particles concentration gradient	Fick’s First Law
Diffusion is direct result of __	Brownian motion
Manner in which the rate of reaction varies with the concentration of the reactants	Order of Reaction
1 Rate is directly proportional to the concentration of the drugs undergoing reaction 2 Rate of reaction is directly proportional to the square of the concentration of one of the reactions	1 First Order Kinetics 2 Second Order Reaction