Water Potential Potential energy of water per unit area compared to pure water

Water Potential = Allows us to determine where water is going to flow due to osmosis, gravity, pressure surface tension Into or out of cell?

Na+ and Cl- ionize and are surrounded by hydration shells Opens up all these excess spaces Decreases water potential

Water leaves the cells of the slug Pure water = 0 Water moves from greater water potential to less

Distilled H 2 O = 0 bars Roots = -2 bars Stems = -6 bars Leaves = -15 bars Atmosphere = bars

More solute drops potential – Because it opens up spaces for water to flow in Physical pressure – Plant’s cell walls put pressure back on water (+ because it is pushing water out) -5 bars 2 bars = -3 bars = -3 bars

ψ s = -iCRT i = ionization constant (for sucrose, this is 1 because sucrose does NOT ionize in water C = molar sucrose concentration at equilibrium (determined from your graph…the point at which your line (of best fit) crosses the x-axis. R = pressure constant ( liter bar/mole °K) T = temperature in Kelvins (273 + °C)

The molar concentration of a sugar solution in an OPEN beaker has been determined to b 0.2 M. Calculate the solute potential at 22  C. i = 1 (sugar does not ionize) C = 0.2 moles/liter (M) R = liter bar/mole K T = K What is the OVERALL water potential? Pressure potential = 0 in open container…

% CHANGE IN MASS OF POTATOES (1 st period) Solution Solution Color % ∆ in Mass Molarity Type of Solution Temp(K) APurple-13%0.6Hypertonic294 BGreen+24%0.0VERYHypotonic294 CRed-23%1.0VERYHypertonic294 DYellow+4%0.2Hypotonic294 EPink-8%0.4Hypertonic294 FBlue-13%0.8Hypertonic294

% CHANGE IN MASS OF POTATOES (4 th period) Solution Solution Color % ∆ in Mass Molarity Type of Solution Temp(K) APurple-18%0.6Hypertonic294 BGreen+16%0.0VERYHypotonic294 CRed-33%1.0VERYHypertonic294 DYellow+6%0.2Hypotonic294 EPink-14%0.4Hypertonic294 FBlue-24%0.8Hypertonic294