Final answer:
To calculate the water potential of the potato, we find the solute potential by using the formula Ψs = -iCRT, considering the starch concentration and temperature.
Step-by-step explanation:
To calculate the water potential of the potato, we need to take into account the solute potential (Ψs) due to the difference in starch concentration inside and outside the potato. Water potential is the measure of the potential energy in water and determines the direction of water movement. It is the sum of pressure potential (Ψp) and solute potential (Ψs).
Since only the osmotic/solute potential is relevant in this problem (pressure potential is typically zero for open containers), we use the formula:
Ψs = -iCRT
Where:
- i is the ionization constant (for starch, i = 1 because it does not ionize in solution),
- C is the molar concentration (1.5M for the potato, 0.65M for the surrounding solution),
- R is the ideal gas constant (0.0821 L·atm/K·mol),
- T is the temperature in Kelvin (25 degrees Celsius + 273.15 = 298.15 K).
For the potato:
Ψs = -(1)(1.5M)(0.0821 L·atm/K·mol)(298.15 K)
Ψs = -36.7 atm
For the beaker solution, one would perform the same calculation with 0.65M concentration to find its solute potential. Then, the water potential of the potato would be the difference in solute potential between inside and outside of the potato, showing the direction of osmosis.