# Finding the concentration of a Potato cell.

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Aim

The aim is to find the concentration (mole/dm3 (M)) of solute in a potato cell by using the process of osmosis and different concentrations of sucrose solution.

Background information

Osmosis is diffusion of water across a partially permeable membrane. It moves from a solution with less solute concentration (high water potential) to a solution with more solute concentration (low water potential). The one with a high water concentration is called a hypotonic solution and the low water concentration is called hypertonic solution, but these only depend on what type of concentration is on the other side of the partially permeable membrane. When more water passes through to one side of the membrane it is called net movement.

(Toole +
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I think this because I know roughly that a potato has a solute concentration of more than 0.3M. As the concentration goes above 0.6M I predict the potato cylinder will loose mass because the potato is most likely to have a smaller concentration than 0.6M. I know the concentration of a potato roughly but all the potatoes are different so I have left a space in my concentration of a potato cell prediction as the real result will vary between these values. My prediction is that the potato 's solute concentration will be somewhere in between 0.3M and 0.6M. This leads me to think of the resulting graph to have a best fit line which has negative correlation and falls as the concentration decreases. I know this because osmosis works in a way that water molecules move from a low solute concentration to a high solute concentration.

Preliminary experiment

For this I was advised to use 5cm of peeled potato (a diameter of 1.2cm), distilled water and 1M sucrose solution. I had to make two potato cylinders and leave one in water and one in a 1M solution (each 30ml) for 15 minutes. I got the percentage change by measuring the potato 's length before and after the experiment. I did this to give me a rough idea of what to expect from this experiment and to change any variables to keep constant for my main experiment, like the time or the initial length. I carried this out and got this result (on a graph):

This shows a very simple conclusion that the potato 's