Properties of Liquids Properties of Liquids Definite volume

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: at 25 C (room temp) DH 2 O(l) is 1250 x greater than DH 2 O(g)

• Liquids can be compressed but change in volume is very slight & requires enormous pressure

Viscosity • Liquids exhibit viscosity Viscosity = resistance to flow

• Viscosity depends on: – strength of attractive forces – sizes & shapes of molecules & – temperature

• As temperature , viscosity – Easier to flow • As temperature , viscosity – More difficult to flow

• Oil in engines prevents direct metal to metal contact • thin film oil on surfaces needed to prevent flaking of metal • oil too thick: won’t circulate at low temps • oil too thin: lose film strength at high temps

Surface Tension Particles at surface of liquid: - exist in unbalanced environment - no attraction from above to balance attractions from below

Surface Tension • Surface Tension = Energy required to ↑ surface area = measure of inward pull • Strong attractive forces High surface tension

Capillary Action • Upward movement of liquid in narrow tube = capillary action

• meniscus of liquid: Concave vs Convex

Force(H 2 O-glass) Force(H 2 O- H 2 O) Force(Hg-glass) Force(Hg-Hg)