LAB REPORT Diffusion and Osmosis through Nonliving Membranes BIO 116-02 02/14/13 Introduction: The following experiment provides information on the movement of water (osmosis) and solutes (diffusion) through differentially permeable membranes called dialysis sacs. Dialysis sacs have pores of particular size not as selectivity of living membranes depends on more than just pore size, but using the dialysis sacs allowed us to examine selectivity due this factor. So this lab experiment showed us visually, how diffusion and osmosis took place and we have been proved our hypotheses by few tests such as Benedict’s test, AgNO3 test, also via testing total weights of dialysis sacs after experiments. Materials and methods: We had four dialysis sacs, small funnel, 25-ml graduated cylinder, fine twine and four beakers (250ml). Solutions: distilled water, 40% glucose solution, 10% NaCl solution and 40% sucrose solution.
Allow the mixture to cool for a few minutes then filter it, using either gravity or vacuum filtration. (We shall be using vacuum filtration.) Wash the residue in the funnel once with a little water and collect all the filtrate. 4. Pour all the filtrate and washings into a 250cm3 volumetric flask.
Take the fine soil from the bottom pan of the sieve set, place it into a beaker and add 125mL of the dispersing agent. Stir the mixture until the soil is thoroughly wet. Let the soil soak for at least ten minutes. 2. While the soil is soaking, add dispersing agent into the control cylinder (Sodium Hexametaphosphate 125ml) and fill it with water to the mark.
When the liquid above the precipitate was clear, the solution was tested for completeness of precipitation when a few drops of BaCl2 solution were added from a pipette. Next, filter paper was place into the funnel and streamed with distilled water. A clean 400mL beaker is placed under the funnel and the precipitate was filtered through. When all the precipitate was filtered and removed from the beaker the residue is washed with distilled water. About 3mL of the wash water is collected in a small test tube.
Take purified water to water testing station and record the data 13. Get rid of the remaining water and clean and put away all equipment Prelab Questions - 1. A.) Mixture is a blend of two or more kinds of matter and a compound is made of two or more elements that are chemically bound. B.)
Independent Variables: • The range of pH, between 6-8 pH. Method: 1. Firstly, place the buffer tablets into a test-tube containing 20 ml of water (at room temperature). 2. Once the buffer tablet has dissolved into the water, add 10 ml of starch solution.
Do this one more time the exact same, and then a third time using only 10 mL of the mixture. Each of the three times you do this, extract the liquid. Transfer the liquid into the large 100 mL round bottomed flask that is connected to your simple distillation set up. Distill the tomato paste liquid. Once it is completely distilled, remove your filtered material and add 2 mL of dichloromethane.
OSMOSIS REPORT INTRODUCTION In osmosis, water moves from a lower concentration into a higher concentration, therefore balancing the water out in both concentrations making them isotonic. In this lab we had to figure out, how different concentrations of sucrose will affect the rate of osmosis? In order to answer the question above we had to prove whether the hypothesis was true or not. If sucrose concentration increases in the selectively permeable baggy, then the rate of osmosis will increase. MATERIALS AND METHODS In order to prove the hypothesis we needed to get materials together and follow a step by step procedure.