Lecture 4 Flashcards
(18 cards)
What is a solution
A solution is a homogeneous and transparent mixture involving – solute(s) and solvent
Solute – the dissolved substance.Present in lesser amount
Solvent – the substance in which the solute is dissolved
Present in greater amount
Example: (solid: glucose; liquid: alcohol or gas: CO2)
What can a solution pass through?
Example of this device ?
A solution can pass through a filter
Example:
The kidney acts like a filter for waste in the blood
When blood passes through the kidneys –
A solution of waste and extra water is filtered through the Nephrons (membrane)
Formation of urine
What is concentration?
Concentration is a way to express the amount of solute per unit of solution/solvent
Large amount of solute – concentrated
Small amount of solute – diluted
Concentrations may be expressed several different ways
Percent (%) composition of mass, Molarity, Normality
(Molality)
What is Percent Composition of Mass
% = parts per hundred
% mass/volume
If Solute is solid = grams/100 mL
If Solute is liquid = mL/100 mL
What solution is used as IV fluid replacement?
0.9 g NaCI in 100 mL of solution
This solution is used for IV fluid replacement because it has the same osmolarity as blood
What is Molarity?
Number of moles of solute per liter (1000 mL) of solution
A mole is the gram molecular weight of an element or a compound
Moles/liter (mol/L)
What is solubility?
The ease at which a solute dissolve in a solvent
The maximum amount of solute expressed in grams, that can be dissolved in mL of water at a certain temperature and pressure
High Solubility (soluble)
Example : Sugar and water
Low solubility (insoluble)
Example : Sand and Water
What is a saturated solution?
Solvent holds as much solute as possible at that temperature. Contains all solute that can be dissolved. Undissolved solid remains, can recrystallized
What are supersaturated solutions?
Unstable solution that contains more solute greater than solute solubility. Also has undissolved solute at the bottom.
What are suspensions?
Mixture of two chemicals/substances in which one component will eventually settle out
Suspensions are heterogeneous fluid/mixture
No solute present – one substance does not dissolve into another
Examples – sand in water, blood (blood cells in plasma)
What are colloids?
Mixture in which one substance is divided into minute particles. Tiny particles suspended in a liquid. Colloids do not pass through membranes and will not settle
Examples of colloids – Fog, smoke, homogenized milk
What is diffusion?
The process by which molecules/particles spread from areas of high concentration, to areas of low concentration. When the molecules are even throughout a space – it is called equilibrium
H2S gas will spread/diffuse throughout a room
What is osmosis?
Osmosis is the passage of water molecules / solvent from a dilute solution, through a semi-permeable membrane, to a more concentrated solution
Water molecules move from a hypotonic solution to a hypertonic solution. Solutes do not pass through
What is Osmotic Pressure?
The amount of pressure required to opposes /prevent osmosis when a solvent flows through a semipermeable membrane to establish equilibrium between compartment of differing concentrations.
Pressure placed on the side of the solution with the higher concentration (hypertonic)
What is an Isotonic Solution?
Red Blood Cell (RBC) maintains its shape – concentration inside and outside the cell is the same
What is an Hypotonic Solution?
RBC swell and eventually burst (hemolysis) – water flow from outside to inside the cell where the concentration is higher
What is an Hypertonic Solution?
RBC collapse (dehydrate) and shrink (crenation) – water flow from inside to outside the cell where concentration is higher
What is Osmolarity
Osmolarity: molarity of particles in soln.(osmole/L)
# od osmole/L of solute
Blood Osmolarity = 0.30M glucose or 0.15M NaCl
Unit (osmol/L or Osm/L)
Concentration of all particles in a fluid solution
Usually expressed as osmol/kg or Osm/kg
Urine osmolality test is used to measure the number of dissolved particles per unit of water in the urine
Useful in diagnosing disorders of urinary concentration such diabetes insipidus and in assessing hydration status
