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Name: __________________________Dilutions are an important tool for quickly and accurately creating test solutions spanning a large range of concentrations for dose-response experiments. Dilutions are also important in microbiology, cell biology, and pharmacology. Dilution is the mixing of a small accurately measured sample or stock solution with a large volume of diluent. Serial Dilution is the step-wise dilution of a substance in solution, generally by the same quantity in each step. The most common serial dilutions are 1:2 (doubling), 1:10, 1:100, and 1:1000 (logarithmic). The concentration of the original solution, the desired final concentration, and the volume required are necessary to know when deciding how many dilutions to make. Show your work for all problems, even if you can do it mentally. Use correct units.1) A 1:10 dilution means 1 part of the concentrated solution added to 9 parts of diluent (10 parts total). To calculate the volume of solution and diluent needed to make 10mL of a 1:10 dilution:1. Calculate the volume of each “part” by dividing the total volume (10mL) by the total number of parts (10)=1mL2. Volume of solution: 1 mL/part * 1 part= 1mL solution3. Volume of diluent: 1mL/part * 9 parts= 9mL diluent4. Double check that the solution and diluent volumes add up to the desired total volume. a) What volume of solution and diluent would you use to make 100mL of a 1:10 dilution?b) What volume of solution and diluent would you use to make 96mL of a 1:8 Dilution?2) Dilution Factors are essential mathematical and descriptive tools. They are calculated by finding the reduced fraction of: Aliquot volume/Total volume. Hint: remember there are three volumes at play: aliquot (or solution), diluent, and totala) What is the dilution factor when 12mL solution is added to 36mL diluent?b) What is the dilution factor when 0.2 mL of concentrated solution is added to 3.8 mL diluent? 3) Serial dilutions involve the removal of a small amount of an original solution to another container which is then brought up to the original volume using diluent; this step is repeated (in a “series”). Dilution factors are multiplicative, meaning that multiplying the denominators of each individual dilution will give you the dilution factor relative to the original solution. Using the following tables, diagram appropriate serial dilutions (The original stock solution is dilution 0)a) A series of 4,1:10 dilutions with total volumes of 1000μL (see figure)Dilution NumberAliquot Volume Diluent VolumeTotal VolumeDilution Factor Dilution Factor (vs. Original Solution)0NANANANANA11000μL1:1021000μL1:1031000μL1:1041000μL1:10b) A series of 6, 1:2 dilutions with total volumes of 5mL Dilution NumberAliquot Volume Diluent VolumeTotal VolumeDilution Factor Dilution Factor (vs. Original Solution)0123456c) Instead of using the same dilution factor for each dilution, set up a 1:8 dilution followed by 1:6 and then 1:2 with total volumes of 40mL.Dilution NumberAliquot Volume Diluent VolumeTotal VolumeDilution Factor Dilution Factor (vs. Original Solution)01234) Dilutions and dilution factors are great, but ultimately the values of interest are meaningful measures of concentration (ie mM or cells/uL). The most helpful formula you need to know is C1V1=C2V2 (C1=concentration of 1st solution, V1=volume of 1st solution, C2=volume of 2nd solution, V2=volume of 2nd solution)If you add 25 mL of water to 125 mL of a 0.15 M NaOH solution, what will the molarity of the diluted solution be? Hint: C1=0.15M V1=125mL, C2=unknown, V=150mL (125mL+25mL)b) If you add water to 100 mL of a 0.15 M NaOH solution until the final volume is 150 mL, what will the molarity of the diluted solution be?c) How much water would you need to add to 500 mL of a 2.4 M KCl solution to make a 1.0 M solution?5) Go back to 4)c and label the empty column “Concentration of Dilution” The original solution (Dilution 0) is 192mM caffeine, calculate the concentration of each dilution. ................
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