1. In an experiment with an Ostwald viscometer, the viscosity oftoluene and water at 303 K is 0.6 and 0.8 poise.The times offlow of water and toluene are 41 s and 34.5 s. The density of wateris 1.002 g/cm³. Calculate the density of toluene.

2. When 10.0 mL of water at 293 K is placed in an Ostwaldviscometer, it takes 136.5 s for the liquid level to drop from thefirst mark to the second. For 10.0 mL of hexane at 20°C in the sameviscometer, the corresponding time is 67.3 s. Find the viscosity ofhexane at 293 K and 1 atm. Data at 20°C and 1 atm: viscosity ofwater = 1.002 cP, density of water = 0.998 g/mL, density ofhexane = 0.659 g/mL.

3. Explain how the viscosity of a liquid changes withtemperature.

4. The viscosity of a colloid is 0.001661 Pa-s at 273 K and0.001376 Pa-s at 308 K. What is the enthalpy and viscosity at 323K? The temperature dependency of viscosity followsthe Arrhenius equation form.