Exam 2 Flashcards
What is a mole?
The molecular weight of a substance in grams (6.02x10^23 particles)
What is molarity?
The number of moles of a solute in one liter of solution
What is molality?
The number of moles of solute in 1000g of solvent
Why is molarity temperature dependent?
The density will change with temperature and molarity is measured in a volume of solution (D=m/v)
What are electrolytes?
Minerals which carry an electric charge when dissolved in water
What are miliequivalents
Measure of the chemical activity of an electrolyte
What are millequivalents dependent upon?
Valence of electrons
What are milliequivalents used to express?
The concentration of solutions of electrolytes
What is an equivalent weight?
The amount of substance that will combine with or displace a given weight of another substance
How would you get one-gram equivalent?
Atomic Weight over valence (the charge it carries)
Why are molecules hydrated?
To improve crystalline stability
What is osmolarity?
The concentration of solution expressed as the number of particles per liter
(combines molar concentration and osmotic pressure)
What is osmotic pressure
When solvent levels are different across the membrane so pressure is created
What happens to osmotic pressure when the solute is a nonelectrolyte?
The solution contains only molecules so the pressure varies with the concentration of the solute
What happens to osmotic pressure when the solute is an electrolyte?
The solution contains ions so the osmotic pressure varies with concentration of solute and its degree of dissociation
Do undissociated molecules exert more pressure than dissociated?
No since solutions that dissociate present a greater amount of particles, they exert a greater osmotic pressure
What is the osmolarity when the solute is a non electrolyte?
The same as the molar concentration because there is only one particle
What happens to osmolarity when the solute is an electrolyte?
It increases because of the increase in the number of particles due to dissociation of the solute
What is the difference between osmolarity and osmolality
Osmolality is temperature independent
What is a bioassay?
A biological testing procedure to estimate the concentration of a drug by measuring the biological response it produces
What are some drugs that use units for its strength?
Antibiotics
Vitamins
Endocrine products
What does potency compare?
The relative strength of a drug to produce the reference standard
How is potency expressed?
In terms of the amount of a drug required to produce an effect of given intensity
What are biologics?
Preparations produced from a living source (vaccines)
What is a solution?
Chemically and physically homogenous mixture of 2 or more substances
What does homogenous mean?
Term used to imply that a mixture is uniform (all parts are identical)
(physically and chemically stable)
What is a binary solution?
Mixture of only 2 components (solute and solvent)
What is usually the solvent for oral solutions?
Water
What are examples of oral solutions?
elixirs
syrup
How does one take parenteral solutions?
By injection (sterile)
What are the advantages of solutions?
Faster onset
Good for elderly and children
Homogeneous
Flexibility with dosing
What are the disadvantages to solutions?
Bulkiness (weigh alot)
Leakage from container
Less stable (can evaporate)
More pronounced taste
What is normality based on?
Chemical activity
What are ideal solutions?
Solutions for which there is no change in the physical properties of the components other than dilution when they are mixed
What are the three main points to an ideal solution?
No heat is given off or taken in
Volume does not shrink or expand
Final volume is the sum of the component volumes
What does raoult’s law state?
The vapor pressure of each volatile constituent is equal to the vapor pressure of the pure constituent multiplied by its mole fraction in the solution
What are real solutions?
Solutions for which changes in the physical properties of the solution occur when the components are mixed
What kind of relationship is shown for ideal solutions?
linear
What kind of line is shown for Raoult’s law for real solutions?
A curve up or down (depending if there are stronger adhesive or cohesive attractions )
How do most solutions in the pharmacy behave?
Nearly like ideal solutions when they are mixed
What is the difference between positive deviation and negative deviation?
Positive = cohesive forces predominate (wants to stay together - alcohol and water) Negative = adhesive forces predominate (wants to bind to other things -HCL/water)
What does positive deviation between alcohol and water result in?
Volume reduction
want to stay together since they share H-bonds so they are more compact
Why do solutions with non electrolytes not conduct currents?
They do not contain ions
How do strong electrolytes dissociate in solutions?
Completely and are 100% ionized
What kind of electrolytes are in most drug solutions?
Partially ionized/ weak electrolytes that have induced dipoles
How do the physical properties of solutions vary?
Based on the concentration of dissolved solute
What are the 4 colligative properties?
Osmotic pressure
Vapor Pressure Lowering
Freezing point depression
Boiling Point Elevation
What do each of the 4 colligative properties depend on?
Number of particles dissolved in the solution
What is osmosis?
When the concentrations of solute on two sides of a membrane are equalized
What does osmotic pressure depend on if the solute is an electrolyte?
Concentration of the solute and the degree of dissociation
What maintains compartmental balance of body fluid distribution?
Blood pressure and osmosis
What flows freely between compartments that house body fluid?
water
What molecules are the main ions outside of the cell?
Na+ and Cl-
What are the main ions inside the cell?
K+ and( PO4)^2-
What does blood pressure due to liquids in compartments?
Forces liquid into the extracellular compartment
What is colloidal oncotic pressure?
Osmotic pressure including colloidal proteins
What are colloids?
Proteins in the plasm that create a protein based pressure
Where does the systolic reading come from?
It is the higher reading of blood pressure form the arterial side (pumped in so higher pressure)
Where does the diastolic reading from blood pressure come from?
The venous side (blood pumped out so pressure is lower)
What is the normal figure for body osmolality?
300 mOsmol
What can happen if an IV infusion is not isotonic?
Substantial osmotic differences that can be severe (cell swelling or shrinking)
What happens if the IV infusion is hypertonic?
Crenation of cell shrinkage
What happens if the IV infusion is hypotonic?
The cell swells and can lyse
What is directly affected by tonicity of IV solutions?
Red blood cells
can later cause tissue damage and necrosis or dying of tissues
What is the name for two solutions that have the same osmotic pressure?
Isosmotic
What is isotonic?
When a solution has the same osmotic pressure as a specific body fluid
What is the most commonly used colligative property for preparing isotonic solutions?
Freezing point
What is the accepted freezing point of blood serum and lacrimal fluid?
-0.52 C