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46 Cards in this Set
- Front
- Back
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What are the advantages of using solutions rather than solid compounds? |
-more precise dosages -better control -better tolerated (100% solid lidocaine injected under the skin would hurt!) |
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What is a solution? |
A homogeneous mixture that consists of one or more solutes uniformly dispersed at the molecular or ionic level throughout a solvent |
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What is a solute? What is a solvent? |
Solute: The component of a solution that is understood to be dissolved in or dispersed in a continuous solvent Solvent: component of a solution into which the solute/s are dissolved |
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What is an aqueous solution? How do covalently bonded substances dissolve? How do ionic substances dissolve? |
Aqueous solution = water is solvent Covalent: disperse as individual molecules Ionic: dissociate into ions and disperse as ions among solvent molecules |
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What is the most common solvent? How does it react with solutes? |
Water Forms hydrogen bonds with ions or other polar molecules -completely surrounds ions because of charges |
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Explain the concept "like dissolves like". |
Two substances form a solution when there is an attraction between the particles of the solute and the solvent. -Polar solvents dissolve polar solutes -non-polar solvents dissolve non-polar solutes |
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What is an electrolyte? |
Solution in which molecules undergo ionization during the solution process Will conduct electrical current |
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What is a strong electrolyte? Weak electrolyte? Nonelectrolyte? Which ones will conduct electricity? |
Strong: a solute that dissociates completely into ions when dissolved in water; will have most electrical conduction Weak: Only a few of the dissolved molecules separate producing a small number of ions in solution (ex. HF(aq.)); will conduct some electricity, less than strong electrolytes Nonelectrolyte: no ions; will not conduct electricity |
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What is miscibility? What is an example of a miscible solution? immiscible? |
-2 liquids are miscible if they are soluble in each other in all proportions -water and alcohol are miscible -water and oil are immiscible |
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What is solubility? |
-the property of a solid, liquid or gas solute to dissolve in a solvent -the amount of a solute that can dissolve in a given amount of solvent |
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What 3 factors does solubility depend on? |
-Properties of the solute in the given solution (polar v nonpolar) -temperature: solubility of a gas increases when temp decreases, solubility of a solid increases with increased temperature -pressure: solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid (Henry's Law) |
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Describe Henry's law. |
-the solubility of a gas in a liquid is directly related to the pressure of that gas above the liquid -At higher pressures, more gas molecules dissolve in the liquid (think of a can of pop) |
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What is molecular equilibrium? |
When a solution of gas and liquid let sit, eventually the amount of gas leaving the solution will be equal to the amount of gas entering the solution |
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What is a partition coefficient? |
The ratio of the amount of substance present in one phase compared with another, the two phases being of equal volume and in equilibrium -Temperature must be stated Ex. blood-gas partition coefficient |
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How is solubility coefficient measured? |
-solubility of solids is measured in mass/volume (moles/liter) -Gases easier to use volume rather than mass although volume only has meaning if temp and pressure are known -volume of gas usually corrected to STP |
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What is the Bunsen solubility coefficient? is it used in anesthesia? |
Volume of gas (corrected to STP) which dissolves in 1 unit volume of the liquid at temp concerned, where partial pressure of the gas above liquid is 1 atm -Not used in anesthesia |
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What is the solubility coefficient used in anesthesia? What does it describe? |
Ostwald solubility coefficient The volume of gas (not corrected to STP) which dissolves in 1 unit volume of a liquid at the temp concerned |
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How does temp affect solubility? |
Gases: increased temp, decreased solubility Solids: increased temp, increased solubility |
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What 3 factors does solubility rate depend on? |
-Particle size of the solute: smaller particles have more surface area exposed = dissolve faster -rate of stirring: stirring increases rate of contact between undissolved particles and solvent molecules -Temperature: increased temp increases rate of dissolution (increased kinetic energy) |
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What is enthalpy of a solution? |
The energy change that accompanies dissolving exactly one mole of solute in a given solvent |
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What is the difference between endothermic and exothermic? |
Endo: energy flows into the system Exothermic: energy flows out of the system |
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What is heat? |
Heat is a process, not a product Transfer of energy into or out of a system caused by difference in temperature |
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How do you determine if forming a solution is endothermic or exothermic? |
-Pulling ions apart of ionic substance requires energy- endothermic -Solvation- water molecules surrounding each ion releases energy- exothermic -If tearing apart ions requires more energy, heat of solution will be endothermic (instant cold packs) -if solvation releases more energy than required to pull ions apart- exothermic (hot packs- sodium acetate in water) |
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What is an unsaturated solution? Saturated? Supersaturated? |
-Solution that contains less than the maximum amount of solute -Solution that contains maximum amount of solute] -Solution that contains more solute than saturated solution under same condition (very unstable, heated up to add more then cooled, seed crystal will cause excess to crystallize out) |
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What is concentration? How is it expressed? |
mass of solute per unit volume -molarity, molality, percent by mass, percent by volume, parts per million |
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How is molarity calculated? How is molality calculated? |
Moles of solute/ L of solution = molarity Moles of solute/ Kg of solvent = molality |
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Percent by mass v. percent by volume? |
Mass: Mass of solute/mass of solution x 100 Volume: Vol of solute/Vol of solution x 100 |
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How do you calculate parts per million? |
ppm = Mass of solute/mass of solution x 1,000,000 |
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In regards to electrolytes, how many equivalents are in one mole? |
Number of equivalents in a mole = to charge on ion (ex. Ca++ has 2 equivalents/mol) 1000mEq / 1 Eq |
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If you have a Ca++ content of 40mEq/L, how many mg/L do you have? |
40mEq/L x 1 Eq/1000mEq x 1mole/2Eq x 40g/mole ??? x 1000mg/g = 800mg/L
??????????????????????????????????? You use 40g/mol for Ca++ |
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Compare and contrast a solution, a suspension and a colloid. |
Solution: particles homogenously dispersed, do not settle out, partially bound to solvent particles Suspension: particles are not bound to solvent, particles settle out on standing Colloid: particles dispersed without appreciable bonding, do not settle out on standing |
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Describe the transparency of solutions, colloids and suspensions. |
solution: transparent but often colored Colloid: often translucent or opaque but may be transparent Suspension: often opaque but may appear translucent (cannot be transparent) |
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What is the particle size in solutions? Colloids? Suspensions? |
Solutions: atoms, ions or small molecules; 0.1 - 1nm) Colloids: large clusters of atoms, ions or molecules or very large ions or molecules; 1 - 1000nm Suspension: at least one component may be individually seen with low power microscope (over 1000nm) |
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Can solutions be separated by filtration? Colloids? Suspensions? |
Solutions and colloids cannot be separated by filtration, suspensions can. |
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What is the Tyndall effect? In what type of substance is it seen? |
-Passing strong beam of light through a liquid, beam becomes visible because particles reflect and scatter light Only seen in colloids, solution particles to small to reflect light; can be used to distinguish between solutions and colloids |
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What is brownian movement? Where is it seen? |
Zigzag, irregular motion exhibited by minute particles of matter when suspended in a fluid -the particles of the suspending medium are in constant motion and continually bombard the solute particles keeping them suspended Only seen in colloids |
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What is the difference between a gel and a sol? |
Gel: strong attraction exists between the colloidal particle and suspending liquid. Mostly liquid yet behave like solids; do not flow easily Sol: Little attraction exists between suspended solid particles and suspending fluid; pour easily (ex. small amount of starch in water) |
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What is an emulsion? |
-Liquid colloidally suspended in a liquid -2 normally immiscible substances -needs emulsifying agent Examples: mayonnaise (oil in vinegar, egg yolk is emulsifying agent), Propofol (soybean oil/propofol mixture in water, egg phospholipid is emulsifier) |
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What do osmolality and osmolarity look at? What is an osmole? How many osmoles is one mole of glucose v one mole of NaCl in a solution? |
-Both look at number of particles in a solution that create osmotic pressure -Osmole: number of moles of a chemical compound that contributes to osmotic pressure -1 mole of glucose = 1 osmole -1 mole of NaCl = 2 osmole (dissociates) |
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What are the units of Osmolarity and Osmolality? |
Osmolarity = osmoles / Liter of solution Osmolality = osmoles / Kg of solvent |
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What is the osmolarity of plasma? What contribute the greatest to plasma osmolarity? What is the osmolarity of LR? NS? |
Plasma: 290 mOsmoles/L (>99% is due to electrolytes) LR: 278 mOsmoles/L NS: 308 mOsmoles/L |
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What is tonicity? |
the relative concentration of solutes in osmotic systems |
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What are some examples of isotonic, hypotonic and hypertonic solutions? |
Iso: NS, LR, Ringers solution Hyper: hypertonic saline Hypo: 0.45%NS, D5W |
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What are considered plasma expanders? |
Hypertonic solutions because they draw fluid into intravascular space |
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What are the 4 colloids used? |
Hetastarch, plasma, dextran, albumin |
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What solutions provide free water? |
All dextrose solutions |
