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Properties of Liquids. Properties of Liquids. Definite volume Indefinite shape Particles close together, but can move little bit Liquids can flow. Density liquids much greater than gases Ex: D H2O(l) is 1250x greater than D H2O(g) at 25 C
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Properties of Liquids • Definite volume • Indefinite shape • Particles close together, but can move little bit • Liquids can flow
Density liquids much greater than gases • Ex: DH2O(l) is 1250x greater than DH2O(g) at 25C • Liquids can be compressed but change in volume very slight & requires enormous pressure
Viscosity • Liquids exhibit viscosity • Viscosity = resistance to flow
Viscosity depends on: • strength of IMF • sizes & shapes of molecules • & temperature • stronger the IMF, the higher the viscosity • As temperature , viscosity • As temperature , viscosity
engine oil prevents direct metal to metal contact • thin film oil on surfaces prevents metal from flaking • If oil too thick, won’t circulate at low temps • If oil too thin, will lose film strength at high temps
Where does the marble drop fastest? Slowest? water glycerol
Surface Tension • Particles at surface of liquid exist in unbalanced environment • No attraction from above to balance attractions from below • Surface seeks smallest possible area
Surface Tension • Surface Tension = E required to ↑surface area = measure of inward pull • Strong intermolecular attractions High surface tension
Surfactants • Compounds that lower surface tension of H2O • Disrupt hydrogen bonds between H2O molecules • See video
Capillary Action • Water forms concave meniscus in glass tube • Attractive forces between water and glass > attractive forces between water molecules • Upward movement of liquid in narrow tube = capillary action
Force(H2O-glass) Force(H2O- H2O) Force(Hg-glass) Force(Hg-Hg) CONVEX CONCAVE