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20 Cards in this Set
- Front
- Back
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What is the difference between Qualitative analysis and Quantitative analysis?
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Qualitative Analysis - What is present?
- Reveals the chemical identity of the species in the sample Quantitative analysis - How much is present -Establishes the relative amount of one or more of these species (analytes) in numerical terms. |
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What is the typical steps in Quantitative Analysis
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Contemporary Analysis
-Chemical principles -Instruments -Electronics -Practiced judgments Method Selection -governed by complexity of sample -number of components in the sample -accuracy you need for your analyte Sampling -types of samples -evaluate well-being, manage treatment, prognose pathology Preparing the sample -Timing -Container -Atmosphere -Light -Storage (freeze, refrigerate, etc) Replicate sampling Eliminate interference -includes (IV fluid, hemolysis, lipids) - above can be removed by diluting or using smaller sample size. Calibration & measurement -Standards (Primary -1; Secondary -2; Calibrator - set instrument to assigned value) -enable us to determine concentration of analyte. |
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What is an interference?
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An interference is a substance that causes an error in analysis by enhancing or attenuating the quantity being measured.
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What is the difference between Primary, secondary, and calibrator.
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-Primary is super pure
- Secondary: purity is established by reference method or chemical analysis -Calibrator: compound containg multiple constituents. |
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What is molarity?
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The number of moles of solute in 1 Liter of solution
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What is a mole?
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The gram weight of the solute divided by its gram molecular weight
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How to convert Molarity & Normality?
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N = nM
where: -N = normality -n = valence -M= molarity |
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What is Normality
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- Accounts for the interaction of dissolved solute with the solvent
- is by the number of equivalent weights per liter, not moles per liter N = [grams of solute/(gmw/valence)]/volume (in L) N = Eq/L |
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What is the gram equivalent weight?
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gram equivalent weight = gmw/valence
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What is the normality of a solution containing 98.0 g of H2SO4 in 0.250 L of solution?
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gram equivalent weight = gmw/valence
--> = 98.08 gmw/ 2 valence = 49.04 N = [grams of solute/(gmw/valence)]/volume (in L) N = (98 grams/49.04 geqw)/0.250 L --> = 8.00 Eq/L |
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How do you calculate %w/w?
How to calculate the amount of solvent(to be weighed)? |
%w/w = gram of solute/ 100.0 g of solution
solvent = 100.0 - grams of solute. solution = solute + solvent - once the amount of solvent is determined, the solvent and solute are combined and mixed together. -%w/w is most accurate --> conc. not flucuate with temp. |
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How many grams of NaOH are needed to make a 30.0% w/w solution using deionized water as the solvent?
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30.0% w/w = grams solute / 100.0 g solution.
gram solute = 30.0 grams of NaOH Prepare: dissolve 30.0 gram of NaOH into 70.0 grams of deionized water. |
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How to calculated %w/v?
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%w/v = grams of solute/ 100 mL of solution.
- most fequently used percent solution in clinical laboratory. - the amount of solute is weighed on a balance and then placed into a 100 mL volumetric flask in which there is a small amount of solvent to dissolve solute --> add to calibration mark. |
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What is quantity sufficient (qs)?
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Used in laboratory to describe the addition of the solvent to the calibration mark.
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What is the %w/v of a solution that has 25.0 g of NaCl dissolved into a total volume of 100 mL deionized water?
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%w/v = gram solute / 100 mL solution
%w/v = 25.0 g NaCL/ 100 mL solution = 25.0% Prep: 25 gram NaCl dissolved in 100 mL water. |
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How to calculate %v/v?
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%v/v = mL solute/ 100mL of solution
solvent = 100 mL total volume - amount of solute. |
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How many milliliters of EtOH are needed to make a 75.0% solution using deionized water?
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75.0% v/v = mL solute /100 mL solution
--> mL solute = 75.0 mL EtOH solvent = 100 mL total volume - 75.0 mL EtOH = 25.0 mL water Prepare: 75.0mL EtOH added to 25.0 mL of water to make 75% v/v EtOH. |
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How to calculate percent calculations to molarity?
Convert 0.85% w/v NaCl to molarity |
1. ratio:
(0.85/100 mL) = (x/1000mL) --> x= 8.50 grams NaCl 2. Molarity formula (moles/L) M = (gram solute/gmw solute)/ 1L = (8.50 gram/58.44 gmw)/1L = 0.14M. |
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What is the formula used to change concentration between solutions (e.g dilutions)?
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(C1)(V1) = (C2)(V2)
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A solution with 350 mL of 2.0%w/v NaCl is needed.
In the stock room is a 5.0 %w/v NaCl. How many mL of 5.0%w/v NaCl is nee to make 2.0% w/v solution? |
(C1)(V1) = (C2)(V2)
(5.0%w/v)(V1) = (2.0%w/v) (350mL) V1 = 140 mL Prepare: 140 Ml of the 5.0%w/v solution are diluted with water to a total volume of 350 mL. |
