2. Experiment (1) B) Determination of Absolute and Relative viscosities of ethanol

3. Viscosity Viscosity is a measure of a fluid’s resistance to flow.

4.  The greater the viscosity the more slowly the liquid flows.  Liquids that have strong intermolecular forces have higher viscosities than those that have weak intermolecular forces.

6.  F α Av/d  F = ɳ Av/d, where ɳ is coefficient of viscosity. poise.  Unit of viscosity is poise.  Poise : The force (F) necessary to move a layer of liquid of area (A) 1cm 2 with a velocity (v) of 1cm/sec past another layer at distance (d) of 1cm.

7.  ɳ 1 = π r 4 p 1 t 1 / 8 v L (ethanol)  ɳ 2 = π r 4 p 2 t 2 / 8 v L (water) ɳ 1 \ ɳ 2 = p 1 t 1 / p 2 t 2 Relative viscosity: ɳ 1 \ ɳ 2 = d 1 t 1 / d 2 t 2 Relative viscosity: ɳ 1 \ ɳ 2 = d 1 t 1 / d 2 t 2

8. Factors effect on viscosity  Temperature  Volume of molecules.  Intermolecular force.  Hydrogen bonds.  Pressure.

9. Results ɳ 1 = ɳ 2 *(d 1 t 1 / d 2 t 2 ) ɳ 1 \ ɳ 2 = d 1 t 1 / d 2 t 2 t2t2 t1t1 ɳ2ɳ2 d2d2 d1d1T 25 30 35 40