NaCl solutions Essay Example for Free

NaCl solutions Essay The different concentrations of NaCl solutions led to the net movement of water molecules in the samples through osmosis. The samples soaked in higher NaCl concentrations, 0. 75 M and 1 M, slightly increased in mass due to less absorption of water. Samples soaked in less NaCl concentrations, on the other hand, became bulky due to considerably high absorption of water. As discussed by Bowen (2000), water molecules flow from the solution with low solute concentration to the part with higher concentration of the solute. Thus, there was a higher net water movement towards the fruit in solutions with low NaCl concentrations than in solutions with high NaCl concentrations. Therefore, water flows in response to the differences in molarity across a samples’ membrane. When sufficient water molecules moved to equalize the NaCl concentration on both sides of the membrane, equilibrium is reached and the net flow of water ceases. The Effect of Solute Concentration on Plant Cells The process of substance’s diffusion across the cell membrane is called osmosis. Osmosis is important to plants because low water content in their cells causes withering. This happens when water moves out of the cells by osmosis. Without enough water there is little pressure inside the cells (turgor pressure) through the vacuoles, thus, the plant sags. By, watering the plant, its cells become engorged with water, giving a firmer body for the plants. The Effect of Solute Concentrations on Red Blood Cells When red blood cells were placed in distilled water, it rapidly absorbed water until it bursts (plasmolysis), hence, cloudy appearance was observed. The distilled water represented hypotonic solution, hence, its molecules moved into the cells. This is the reason why plasma, the liquid portion of our blood is made of water with dissolved salts and proteins to prevent the unnecessary gain or loss of water by our blood cells. Discussion and Conclusions Diffusion in a Solid and in a Liquid Based on the results of this experiment, the rate of diffusion of solid particles is affected by its molecular weight. Since methylene blue has a higher molecular weight than KMnO4, it diffused slowly. The medium on which the particles diffuses, also affect the rate of diffusion. Liquid medium favors diffusion more than hardly vibrating solid particles. This is the reason why KMnO4 diffuses faster in liquid medium than in agar. Moreover, the temperature which denotes kinetic energy of the particles affects the particle movement. Particles in high temperatures or with high kinetic energy, move and diffuse faster that particles in low temperature. The Effect of Solute Concentration on Plant and Animal Cells The net movement of materials in and out of the cell is affected by the concentration of the solute. Based on concentration gradient, water flows from area of low solute concentration to region of high solute concentration. Thus, when the plant cells were exposed to a solution of low solute concentration (hypotonic), water flowed into the cell. The swelling of elodea plant in distilled water is an indication of the high solute concentration in its cells. Meanwhile, the cloudy appearance of the red blood cells in distilled water indicates plasmolysis or bursting due to the excessive absorption of water. The cell membrane protected the plant cells from bursting. References All About Agar. (n. d. ). Science Buddies. Org. Retrieved October 30, 2008, from http://www.sciencebuddies. org/mentoring/project_ideas/MicroBio_Agar. shtml Bowen, R. A. (2000). Osmosis. Retrieved October 30, 2008, from http://arbl. cvmbs. colostate. edu/hbooks/cmb/cells/pmemb/osmosis. html McCandless, Jr. J. R. (1997). Diffusion, Osmosis and Cell Membranes. Science Education Connection. Retrieved October 30, 2008, from http://biology. arizona. edu/sciconn/lessons/mccandless/reading. html Senese, F. (2007). Matter. General Chemistry Online. Retrieved October 30, 2008, from http://antoine. frostburg. edu/chem/senese/101/matter/index. shtml