Notes: Special Properties of Liquids (13.1/13.3 add-on) OBJECTIVES: Students will be able to (SWBAT) Explain special properties of liquids due to IMFs QUESTIONS TO PONDER: How is viscosity and surface tension affected by IMFs? Explain how IMFs are related to the use of chromatography?

Special Properties of Liquids Viscosity Surface Tension Capillary Action

Viscosity Resistance of a liquid to flow because of IMFs High viscosity  thick  flows more slowly Honey, syrup Low viscosity  more “liquidy”  flows more rapidly Water, many other liquids As temperature increases, viscosity will decrease (flows faster)  less IMF because particles are farther apart

Surface Tension Liquids particles of surface sticking to each other due to IMFs  cohesion Molecules at or near the surface tend to contract the surface into smallest possible area

Surface tension is the reason for… Ability to walk on water Beads of droplet form Belly flops

Capillary Action Ability of liquid to flow up narrow spaces opposite gravity Occurs due to IMF between liquid and solid surface it is in contact with  adhesion If adhesion > cohesion  goes up Reason for water going up stems of plants

Capillary Action Reason for water going up stems of plants

Chromatography A lab technique that uses capillary action to separate mixtures Separates mixtures based on different polarities of molecules and IMFs ↓ polar  travels farther up (repelled by solvent) ↑ polar  doesn’t travel up as far (attracted to paper and solvent)