Physical properties

Question 1

Solution

Answer 1

homogeneous mixture of two or more substances in a single phase. Solute in a solvent

Question 2

Dissolution

Answer 2

process of dissolving a solute in a solvent to form a solution. physical change

Question 3

Solubility

Answer 3

max concentration of a solute that can dissolve in a solvent is saturation. Affected by concentration, temperature, pressure, polarity

Question 4

Dissolution process

Answer 4

breaking solute bonds (endothermic) and forming solute-solvent bonds (exothermic). Ions are solvated (hydrated in water) to create ion-dipole bonds.

Question 5

Concentration

Answer 5

amount of substance in defined space.

Question 6

Molarity

Answer 6

mol/L

Question 7

Molality

Answer 7

mol/Kg

Question 8

ppm

Answer 8

1mg/1kg or 1mg/1L

Question 9

Viscosity

Answer 9

resistance of liquid to flow. high viscosity = thicker. caused by internal friction between molecules

Question 9

Viscoelastic materials

Answer 9

all formulations are characterised by a viscos and elastic component - spring and dashpot model

Question 10

Shear force

Answer 10

force acting in perpendicular direction parallel to the body.

Question 11

Two plate model

Answer 11

shows how liquid performs under shear force, keeps it intact and creates laminar flow

Question 12

Laminar flow

Answer 12

molecules move in orderly layers

Question 13

turbulent flow

Answer 13

no pattern to the flow at all

Question 14

Shear stress

Answer 14

result of shear force over area.
T = F/A

Question 15

Shear rate

Answer 15

Velocity as a result of stress and force applied. y = v/h

Question 16

Newton’s viscosity law

Answer 16

proportional shear stress creates perpendicular shear flow and shear rate.

Question 17

Shear flow (viscosity)

Answer 17

n = T/y

Question 18

Newtonian fluids

Answer 18

follow newton’s law, flow resistance is independent of external force

Question 19

Non-newtonian fluids

Answer 19

shear dependant, viscosity increases or decreases with shear force.

Question 20

Shear thickening

Answer 20

as force is applied viscosity increases. Dilatant, rheopectic. Eg, oobleck

Question 21

Shear thinning

Answer 21

as force is applied viscosity decreases. Pseudoplastic, thixotropic. Eg, toothpaste

Question 22

Factors that affect flow behavioru

Answer 22

pressure, temperature, time,

Question 23

Rheology

Answer 23

science of deformation of material, how does material respond to force

Question 24

Rheology in formulation

Answer 24

rheometer measures viscosity and viscous behaviour.

Question 25

Viscour behaviour

Answer 25

internal friction between components of flowing fluid. energy dissipates from friction

Question 26

Elastic portion of energy

Answer 26

internal structures extend without overstressing and store energy then the energy is released when triggered and returns to shape

Question 27

How does carbomer work

Answer 27

powder polymer all jumbled up, once hydrated the polymer slightly untangles. When basic solution is added the polymer stretches all the way out from charged ends repelling. Salt returns the polymer back to normal (neutralises basic)

Question 28

Shear strain

Answer 28

deformation of material

Question 29

Storage modulus

Answer 29

elastic portion
G’ = G cos>

Question 30

Loss modulus

Answer 30

viscous portion
G” = G sin>

Question 31

Viscoelastic solids

Answer 31

G’>G”

Question 32

Viscoelastic liquids

Answer 32

G”>G’