The osmotic pressure is 1.66 torr at 21 °C for a solution containing 7.50 mg of a protein dissolved in water to give 10.00 mL of solution. Determine the molar mass of the protein.

A certain liquid X has a normal freezing point of 7.00°C and a freezing point depression constant =Kf 7.41·°C·kgmol−1. A solution is prepared by dissolving some iron(III) chloride (FeCl3) in 700.g of X. This solution freezes at 3.5°C. Calculate the mass of FeCl3 that was dissolved. Be sure your answer is rounded to the correct number of significiant digits.

Calculate the vapor pressure of ethanol, CH₃CH₂OH, in a water solution containing 72.5% ethanol by volume at 19.0 °C. The vapor pressure of pure ethanol at 19.0 °C is 40.0 Torr. The density of ethanol is 0.789 g·mL⁻¹ and the density of water is 1.000 g·mL⁻¹.

A protein subunit from an enzyme is part of a research study and needs to be characterized. A total of 0.170 g of this subunit was dissolved in enough water to produce 2.00 mL of solution. At 28 °C the osmotic pressure produced by the solution was 0.138 atm. What is the molar mass of the protein?

Determine the molality of a 25% sodium thiosulfate, Na2S2O3, solution.

Why do colloids exist?  Give specific examples of colloids' applicability.