Fluids, Solutions and Their Behavior - Quiz 1 Flashcards
What are fluids?
- Something that can flow
- Can be liquid or gas
- Basic forces cause fluids to flow
- Assume shape of container
Hydrostatics
Study of fliuds that are NOT moving
Density and Pressure
Hydrodynamics
Study of fluids in motion
Pascal’s Principle
The pressure applied to a confined fluid increases the pressure of the entire fluid by the same amount
Bouyancy
All fluids exert a bouyant force on immersed objects equally on all sides of the object
Archimedes Principle
An object immersed either totally or partially in fluid feels bouyant force equal to the weight of the fluid displaced
If an object sinks, the bouyant force is _____ than the true weight of the object.
If it floats, the bouyant force is ______ than the true weight of the object.
Less
Greater
Hydrometer
A weighted device that measures specific gravity of fluids
Flow Rate
Volume of fluid passing a point per unit time
Units of volume divided by time’
m3/s
Speed and Diameter
- Narrowing of tube causes speed to increase tremendously
- Flow rate remains the same.
- Volumes remain the same, while shapes change
- Fluid flows at greater speed through narrow part of tube
Bernoulli’s Principle
As the speed of a fluid increases, the pressure exerted by the fluid decreases
Fluid pressure is inversely related to speed
EX: Lift of airplanes, show cutains sucked towards you whe you turn on shower
Venturi Tube Flowmeter
Device used to measure fluid speeds in pipes.
Basis for neb treatment delivery.
Viscosity
Measure of a fluid’s resistance to flow
High Viscosity = flow slower
Low Viscosity = flow faster
Poiseuille’s Law
Describes resistance to flow through a tube
- Pressure increases proportional to flow rate & gas viscocity
- Small airway radius and longer distances increase flow resistance
- R = (8 x L x n) / (π x r4) *R: resistance, L: length, n: viscosity, r: radius
- Reducing r by 16% will double R
- Reducing r by 50% will increase R by 16x
***Only applies to laminar flow***
Reynold’s Number
- NR - dimensionless quantity used to characterize fluid flow
- Measures tendency for turbulence to occur, (> 2000)
Relationship of Reynold’s Number to viscosity
Inversely Proportional
Relationship of Reynold’s Number to density, velocity, and tube diameter
Proportional
Solution
Homeogenous mixture that has one or more solutes uniformly dispersed
- Solvent - the larger amount
- Solute - the smaller amount
Molality (m)
m = moles solute / kg solvent
Never equal to Molarity
Useful for physical chemistry
Molarity (M)
M = moles solute / L solution
Never equal to molality
Useful for solution stoichiometry
Solubility
The amount of solute that will dissove in a given amount of solvent
- Like Dissovles Like
- Polar to Polar; Nonpolar to Nonpolar
- EX:
- Lidocaine Hydrochloride soluble in water/blood
- Organic compounds, like most injectable meds, to be relatively insoluble in a water-based medium like blood.
Saturated
Contains the max amount of solute
Supersaturated
Not a stable system
Contains more solute allowed by the solubility
EX: Solid out of solution
Bubbling out as gas
Miscible
When two liquids are soluble in eachother in all proportions
EX: Alcohol & Water
Solvation Process
Energy/Heat required to break/solvate chemical bonds
Energy to break bond > Energy released = Endothermic
Energy released > Energy to break bond = Exothermic
How does pressure effect solubility
Directly Proportional
- For Gas: As pressure increases, solubility increases (w/ constant Temp)
- Henry’s Law
How does Temperature effect Solubility
- Gas: As temperature increases, solubiilty decreases
- Liquids and Solids: As temperature increases, solubility generally increase
Colligative Properties
- Only depend on number of particles, not identity
- Vapor Pressure decrease w/ solute increase
- Boiling Point increase w/ solute increase
- Freezing Point decrease w/ solute increase
- Osmotic pressure increase w/ solute increase
Vapor Pressure
- Results from most energetic molecules at surface escaping to gas phase
- VPsolution < VPsolvent
- Raoult’s Law - VP of volatile component of a solution = VP of pure substance x mole fraction of that substance
Boiling Point Elevation
- Temperature at which VP of the material = ambient pressure
- VP of a solution is decreased by adding nonvolative solutes, a higher temp needed to drive the VP up to where it equals ambient pressure
- Boiling point increases as concentration of solutes increases. - directly proportion to molal concentration of solute.
- EX: Adding salt to water slightly increase BP
Freezing Point Depression
Temperature at which liquid phase of material is in equilibrium with solid phase.
- Molecules/atoms need to settle in an orderly, lattice struture. - presence of solutes interferes by getting in the way
- Need to cool sample to lower temps, lowering kinetic energy, before they settle into solid phase
Osmotic Pressure
- Tonicity - the relative concentration of solutes in osmotic system
- Isotonic - equal concentrations of particles
- Hypertonic - greater concentration
- Hypotonic - lower concentration
- Osmosis - diffusion of water from higher concentration to area of lower concentration
Colloids
- Not true solutions - one phase uniformly dispersed in a second phase
- Particle size: 200nm
- might be super-size molecules or aggregates of ions
- Colloidal particles cant be filtered and do not settle out of solution
- EX: Blood, milk, jelly, albumin
Drug + Salt = Acid or Base?
Weak base
EX: Morphine Sulfate, Lidocaine HCL
