Osmosis Essay

The purpose of this experiment is to investigate the effect of changing the concentration of sodium chloride solution on the rate of osmosis in tubes of potatoes. This was maintained using equal measurements of the potato tubes and applying them into the different concentrations of sodium chloride, 0%, 2%, 5%, 10%, 20% and 26%, in beakers then measuring the change in mass of the potato tubes afterwards. The time taken for all potato tubes to be placed in solution was 15 minutes. Can the concentration gradient of the sodium chloride solution influence on the rate of osmotic diffusion undergone by the potato tubes?

Osmosis is a type of diffusion which is only applied on water and is a passive process which does not require an input of energy from the cell; this is because materials are moving with the concentration gradient. Osmosis is a process that occurs at a cellular level, which entails the spontaneous net movement of water through a selectively permeable membrane, from a region of high to low water concentration, in order to equalise the level of water in each region. This form of diffusion takes place when the molecules in a high concentration are too large to move through the membrane. The term semi-permeable or selectively permeable means that some substances can easily pass through the cell membrane, whereas others cannot. The significance of osmosis to cells is great, since it is the osmotic pressure that maintains the shape of an animal cell and provides support in the plant cells. Many factors affect the rate of osmosis including size of particles and temperature however in this particular experiment the factor investigated is the concentration of sodium chloride. Tubes of potatoes will be used to demonstrate the fact...

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This occurrence can be explained through the process of osmosis. The increase in mass as well as the increase in turgidity, in the potato tubes immersed in low sodium chloride concentration solutions is understood to be a hypertonic. Since the solution is hypertonic, the water molecules will diffuse into the area of lower water concentration (the potato tube) in order to achieve equilibrium. Alternatively, the decrease in mass in the potato tube submerged in highly concentrated sodium chloride solutions can be explained by its immersion in a hypotonic solution. As sodium chloride solution is less concentrated in water molecules than the potato tubes, the decrease in mass and loss of turgidity results from the net movement of water leaving the potato tube, which is higher in osmotic pressure, and diffusing into the solution.