This decrease in mass can be explained by exosmosis, where water leaves the cells of the potato due to there being lower water potential in the sucrose solution than the potato cells. (see Fig 2). For 0.3M the average percentage change in mass was -0.88%. This then decreased as the concentration of sucrose increased, with 1.0M having an average percentage change of -30.48%.
This decrease in the average percentage change is mass is due to the fact that as the concentration of sucrose solution increases, the water potential of the solution decreases so that more water molecules move into the sucrose solution from the potato cells by exosmosis. These results show different water potentials at 0% change in mass than in the preliminary experiment because the potato used is a different potato to the preliminary. Graph 2 shows that the water potential in the preliminary experiment was -1150kPa. The water potential in this experiment was -600kpa. This difference is because every potato cell will have a slightly different water potential and every potato will have a different overall water potential as some potatoes may contain more water or more sugar than other potatoes. Therefore, it shows that the potato used in the preliminary experiment had cells which had a lower water potential than the cells used in this …show more content…
To increase the accuracy and thus the reliable of the results, a burette or volumetric pipette could be used as these are more accurate pieces of apparatus and have a lower percentage error. A burette has a percentage error of
These errors and uncertainties do not have an effect in the validity of the final conclusions as the results gained from the experiment showed a general pattern which was backed up with scientific knowledge. The precision errors for the apparatus were not large enough to harm the results and the conclusion formed from it. The percentage error from making the concentrations were quite high so they could have affected the conclusions drawn in that the exact concentrations were not used so the results do not show true values for that concentration. However, as stated before when making the solutions it is likely that concentrations were exact as the error when pouring the solution in each time may have levelled out. The concentration not being exact does not affect the conclusions as the results did show a general pattern of decreasing mass when the concentration increased, which was backed up with