Final answer:
To get the molecular weight from an osmotic pressure graph, you need to convert the osmotic pressure to atmospheres and determine the molar concentration. Then, use the II = MRT formula to find the osmotic pressure and subtract the normal osmotic pressure to obtain the additional pressure needed to balance. Finally, use the II = MRT formula again to calculate the molarity of the solute.
Step-by-step explanation:
To get the molecular weight from an osmotic pressure graph, you can follow these steps:
- Convert the osmotic pressure to atmospheres.
- Determine the molar concentration from the osmotic pressure.
- Use the formula II = MRT to find the osmotic pressure, where T is on the Kelvin scale (in this case, convert the temperature to Kelvin) and the value of R is expressed in appropriate units.
- Subtract the normal osmotic pressure from the osmotic pressure of the solution to obtain the additional pressure needed to balance the two.
- Use the formula II = MRT again to calculate the molarity of the solute needed to create this osmotic pressure.
By following these steps, you can determine the molar mass or molarity of the solute based on the osmotic pressure.