Solute potential can be calculated by the following formula:
Ψ = - M × i × R ×T
where M - the molar concentration of the solute, i - the van't Hoff factor, the ratio of amount of particles in solution to amount of formula units, R - the ideal gas constant, T - is the absolute temperature.
As M = 0.3 M, i = 1 (sugar molecules do not dissociate), R = 8.314 (L·kPa)/(mol·K), and T = 27 °C = 300.15 K:
Ψ (sugar) = 0.3 M × 8.314 (L·kPa)/(mol·K) × 300.15 K = 748.63 kPa
Answer: 748.63 kPa