Final answer:
The osmotic pressure of seawater can be calculated using the concentration of NaCl, the molar mass of NaCl, and the gas constant. In this case, the osmotic pressure of seawater at 25°C is 34 atm.
Step-by-step explanation:
Osmotic pressure is a measure of the pressure needed to prevent the flow of water across a semipermeable membrane due to the concentration of solute. To calculate the osmotic pressure of seawater at 25°C, we need to take into account the concentration of NaCl in seawater, as well as the molar mass of NaCl and the gas constant. According to the given information, seawater has a concentration of 35g NaCl / L, which is equivalent to 0.70 M NaCl. As 1 mole of NaCl produces 2 moles of particles, the total concentration of dissolved particles in the solution is 1.4 M. Using the equation for osmotic pressure, II = MRT, where M is the molarity, R is the gas constant, and T is the temperature in Kelvin, we can calculate the osmotic pressure. Plugging in the values, we get II = (1.4 mol/L) [0.0821 (L· atm)/(K · mol)] (298 K) = 34 atm.