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How The Concentration Of A Solution Effects Osmosis.

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Introduction

Biology Investigation. How The Concentration Of A Solution Effects Osmosis. Predictions and Explanations. I predict that when I put the potato in the different solutions, over time each potato will have a different weight. I predict the sugar and salt solutions will weigh less than others and the higher the molar of solution (0.25m, 0.5m, 0.75m, 1m) the lower the potato will weigh when removed from the solution. The water in the solution makes the potato weigh more or less because water either leaves the solution to the potato or leaves the potato to the solution. I think this is because I know that osmosis is the movement of water particles by diffusion from an area of high water concentration (dilute solution) to an area of low water concentration (concentrated solution) through a particially permeable membrane. If I were to plot a graph before doing the experiment I think it would look like this: Concentration of solution Difference in mass I think it would look like this because the more concentrated the solution is, the less it will weigh because the water from the potato will move into the higher concentrated area therefore the potato loses mass which is why my line is moving down slowly. ...read more.

Middle

I will then place one potato in each of the nine test tubes and add the correct concentration ( 0.25m sugar, 0.5m sugar, 0.75m sugar, 1m sugar, water, 0.25m salt, 0.5m salt, 0.75m salt, 1m salt ) of solution to each tube using a measuring cylinder and pipette to measure accurately, and place them in a test tube rack, whilst osmosis is taking place I will add a sticker to each tube to interpret the molar and weight of each tube and potato. I will wait exactly thirty minutes and then empty the solution and potato to place on blue paper to remove any excess water, weigh each potato to see the changes that occur and finally record the changes that occur. Fair Testing. To make sure my experiment is a fair test I will: > Make sure I add the same amount of solution to each test tube, a different amount of solution cold mean different reactions taking place. > Use only one type of potato, a different type could mean different results. ...read more.

Conclusion

I believe this is because the higher the molar (concentration) the more weight it will lose because the water from inside the potato will travel to the higher concentrated area e.g. the solution. My results back my idea up because as you can see the 1m sugar lost 0.30 grams and the 1m salt lost 0.33g. The water potato gained weight because the concentrations are the same in the potato and outside the potato which means water can travel into the potato, as you can see the water experiment gained 0.33g. Final Results. Solution Weight before (g) Weight after (g) Time(m) Difference(g) 0.25m salt 2.77 2.89 30 + 0.12 0.5m salt 2.67 2.73 30 + 0.06 0.75m salt 2.74 2.64 30 - 0.10 1m salt 2.62 2.45 30 - 0.17 Water 2.74 2.89 30 + 0.15 0.25m sugar 2.54 2.73 30 + 0.19 0.5m sugar 2.73 2.87 30 + 0.14 0.75m sugar 2.71 2.76 30 + 0.05 1m sugar 2.73 2.55 30 - 0.18 Analysis. My results show that the higher the concentration of solution the more water is lost from the potato through diffusion, but lower solutions such as water show that the potato gains weight because water from the solution moves into the potato. My Graphs look like this: ...read more.

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