# Chemistry Laboratory 1

 The osmolality of a urine sample or serum specimen is measured by a change in the
 freezing point
 Osmolal gap is
 the difference between the calculated and measured osmolality value
 The formula for calculating serum osmolality that incorporates a correction for the water content of plasma is
 (2 Na + Glucose / 18) + (BUN/2.8)
 The osmolal gap is defined as measured Osm/kg minus the calculated Osm/kg. The average osmolal gap is near
 zero
 The solute that contributes the most to the total serum osmolality is
 sodium
 An adult diabetic with renal complications has the following results. calculate theoretical osmolalitySodium = 133 mEq/LBUN = 84mg/dLGlucose = 486 mg/dLCreatinine = 5 mg/dL
 (2 Na + Glucose)/ 18 + BUN/2.82 (144) + 486/18 + 84/2.8323 mOsm/kg
 A patient had the following serum results, calculate osmolality:Sodium = 140 mEq/LGlucose = 95 mg/dLBUN = 10 mg/dL
 2(Na) + glucose/18 + BUN/2.82(140) + 95/18 + 10/2.8289 mOsm/kg
 List the 4 colligative properties of solution
 Osmotic pressure, decreased vapor pressure, decreased freezing point, and increased boiling point
 One mole (Avagadro’s number of molecules) of non-ionizing solute dissolved in one kilogram of water will ________ the freezing point by ______degrees C.
 Decrease, 1.86
 The concentrating abilities of the kidney are the best evaluated by
 osmolality
 The osmolality of a solution is dependent upon
 the number of particles
 An increase in the osmolar gap may often be associated with
 ingestion of toxic substances, ingestion of alcohol, presence of ketones
 List the four primary constituents found in serum that are measured by osmometry
 Na+, Cl-. Glucose and BUN (urea)
 Define osmometry
 techniques to measure the concentration of the dissolved solute particles in solution that contributes to osmotic pressure
 When referring to osmolality, what are the units measured?
 mOsm/ kg
 Explain the difference between osmolarity and osmolality
 Both are measurements of concentration of solutes in a solution, but osmolarity is a measurement of the concentration per volume, which is temperature dependent. Osmolality is concentration relative to mass of solution and is temperature independent
x

Hi!
I'm Larry

Hi there, would you like to get such a paper? How about receiving a customized one?

Check it out