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31 Cards in this Set
- Front
- Back
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Interface |
Boundary between 2 phases |
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Surface tension |
Force that pulls the molecules at the interface together, w/c results to the contraction of the surface |
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Dynes/cm N/m |
Unit for surface tension |
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Interfacial tension |
Force per unit length existing at the interface between two immiscible lq. Phases |
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Force/ length of the surface |
Formula for surface tension |
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Surface free energy |
This energy increases when surface of the same mass of liquid increases |
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Capillary rise Du Nuoy Ring method |
2 measurements of surface and interfacial tension |
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Y= 1/2 hgrd |
Formula for capillary rise |
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Y= dial reading in dynes/ 2 x ring circumference x Beta |
Formula for Du Nuoy Ring method |
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Du Nuoy Ring method |
This method depends on the principle that the force necessary to detatch a platinum- iridium ring immersed at the surface or interface is proportional to the surface or interfacial tension |
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Tensiometer |
Other name for Du Nuoy Ring method |
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Surface active ingredients |
Molecules or ions that are absorbed at interfaces |
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More hydrophilic |
Higher the hlb= ? |
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More lipophilic |
The lower HLB= ? |
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Tweens (polyoxyethylene) Derivatives of spans) |
Example of high hlb substance |
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9.6- 16.7 |
Value for high hlb |
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Span sorbitan ester |
Example of low hlb substance (2) |
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None |
Interfacial tension of G-G |
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Gamma LV |
Interfacial tension of G-L |
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Gamma SV |
Interfacial tension of G-S |
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Gamma LL |
Interfacial tension of L-L |
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Gamma LS |
Interfacial tension of L-S |
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Gamma SS |
Interfacial tension of S-S |
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No possible interface |
Type and example of G-G interface |
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Lq surface, body of water exposed to atmosphere |
Type and example of G-L interface |
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Solid surface, table top |
Type and example of G-S interface |
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Liq- liq interface, emulsion |
Type and example of L-L interface |
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Liq solid surface, emulsion |
Type and example of L-S interface |
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Solid- solid interface, powder particles in contact |
Type and example of S-S interface |
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Amphiphile |
Molecule or ion has a certain affinity for both polar and non polar solvents |
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1.7- 8.6 |
Hlb value range with low hlb |
