Results
%Δ mass = (mass final – mass initial) / mass initial
Beaker containing Initial mass Final Mass Mass difference %change in mass
Distill water 1.38g 1.60g 0.22g 15.94%
0.2M 1.40g 1.40g 0g 0 %
0.4M 1.36g 1.18g -0.18g -13.24%
0.6M 1.31g 1.06g -0.25g -19.08%
0.8M 1.40g 1.14g -0.26g -18.57%
1.0M 1.29g 0.83g -0.46g -35.66%
The results were presented on a graph against the percentage change in mass against the concentration of sucrose molarity
The molar concentration of the potato cell is 0.2M
The solute potential can be find using the formula given below
Ψ = -iCRT where
i = the ionization
C = molar sucrose concentration at equilibrium
R = pressure constant (0.0831litres bar per mole
T = temperature K (273 + ℃)
Givens
i= (-1) (0.2M) (0.0831) (25℃ +273 = 298℃)
= -4.9527
Ψ = -4.94 bars
Explain how you would determine the molarity of a potato
In the given data, the molarity of the potato cell is determined to be 0.2M based on the percentage change in mass. The concentration where the percentage change in mass matches that of the potato cell is the molarity of the potato.
Complete the post lab questions
a.if all the potatoes cores allowed to dehydrated, by sitting in the open air would the water potential of the potato cell decrease or increase. Why?
If the potato cores are allowed to dehydrate by sitting in the open air, the water potential of the potato cell would decrease. This is because the water potential is a measure of the potential of water to move from one place to another, and as the potato cores lose water and dehydrate, there would be a decrease in the amount of free water molecules available in the cell. This would result in a decrease in the water potential of the potato cell.
b.If the plant cell has the lower water potential than its surrounding environment and if pressure is equal to zero, is the cell hypertonic (in terms of solute concentration) or hypotonic to its environment. Will the cell loss or gain water?
The cell would be hypertonic to its environment in terms of solute concentration. Since water moves from areas of higher water potential to lower water potential, the cell would lose water to its environment.
c.if the water potential for the sucrose solution is dialysis bag is -6.25 bars and it is immerse in the cup of sucrose solution having a water potential of -3.36 bars and if the water potential inside and outside the bag is zero, will the bag gain or lose mass. Explain your answers
The bag will lose mass. This is because water will move from the area of higher water potential (-3.36 bars) to the area of lower water potential (-6.25 bars) in an attempt to reach equilibrium. Since the water potential inside and outside the bag is zero, water will move out of the bag into the sucrose solution, causing the bag to lose mass.
using the information in the result section, write a good discusion in a practical
The results of the experiment showed that as the concentration of the sucrose solution increased, the percentage change in mass of the potato cores also increased, indicating a decrease in water potential in the potato cells. This is because water moves from areas of higher water potential to lower water potential, in this case, from the potato cells to the more concentrated sucrose solution.
The molarity of the potato cell was found to be 0.2M based on the percentage change in mass. By comparing the percentage change in mass of the potato cores with that of the sucrose solutions of different concentrations, it was determined that the molarity of the potato cell matched that of the 0.2M sucrose solution.
In terms of practical implications, these results highlight the importance of understanding water potential and its effects on plant cells. By measuring the percentage change in mass of potato cores in different sucrose solutions, it is possible to determine the molarity of the potato cell and gain insights into the water potential of plant cells.
The experiment also demonstrated the concept of osmosis, where water moves across a semi-permeable membrane from areas of higher water potential to lower water potential. This is crucial for understanding how plants regulate water uptake and maintain turgor pressure in their cells.
Overall, the experiment provided a practical way to determine the molarity of a potato cell and illustrated the principles of water potential and osmosis in plant cells.