Puzzled by her discovery, the scientist decided to expand on her experiment by t
ID: 196542 • Letter: P
Question
Puzzled by her discovery, the scientist decided to expand on her experiment by testing similar mechanisms as the one described above, using dialysis bags. Dialysis is a process through which medical doctors use machines to help filter the blood of patients whose kidneys have become dysfunctional. Dialysis bags are essentially pieces of flexible porous tubing, with pore size ranging from approximately 10 to 100 Angströms. Although not completely identical to cell membranes, dialysis tubing may sometimes be used to address questions related to osmotic forces across a semipermeable membrane. Water and small molecules can cross the membrane of dialysis bags, while larger molecules (larger than 100 Angstroms) are unable to pass through the pores. In this experiment, the scientist filled each of fve dialysis bags half full with one of the following substances. See sketch below. Bag # Contains Glucose Starch Albumin Titin Glass beads 5% by wei 5% by weight 5% by weight 5% by weigh 5% by weight Bag 2 The final weight of each bag is 100 g The scientist placed the dialysis bags into five separate flasks of distilled water so they were completely submerged. After 2 hours, she removed the bags and recorded these weights: 1. Glucose bag: 99.8 g 2. Starch bag: 174.3g 3. Albumin bag: 139.4g 4. Titin bag: 105.8 5. Glass bead bag: 100.3 g Explain the results of each bag. (Consider how much of each substance you are putting in look for molecular weight of glucose, starch, albumin, and titin). Remember that various starches may have different molecular weights based on the size of the glucose chains (just get a feeling for a reasonable range of molecular weights). Keep in mind that the weight of proteins is often expressed in Daltons (Da) or KiloDaltons (kDa) 1 Da 1g/mol. (5 points) 1. Glucose bag 2. Starch bag: . Albumin bag: 4. Titin bag: 5. Glass beads bag: If you wanted to estimate the molar weight of an unknown organic compound that you just discovered, how could you design an experiment to assess it? (2 points)Explanation / Answer
Answer:
1) Based on the given information:
Dialysis tube is a semi-permeable membrane with selective permeability
Amount of substance that we are putting in:
2) Freezing point depression technique can be used to determine the molar mass of an unknown substance.
Bag# Composition Amount (by weight) Weight of bag (g) before dialysis Weight of bag (g) after dialysis 1 Glucose bag 5% 100 99.8 2 Starch bag 5% 100 174.3 3 Albumin bag 5% 100 139.4 4 Titin bag 5% 100 105.8 5 Glass beads bag 5% 100 100.3Related Questions
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