Test Number 4 Flashcard

Exothermic changes in state- energy and heat is lost
Freezing- liquid to solid
Condensation- gas to liquid
Deposition- gas to solid
Endothermic changes in state- needs heat to occur
Melting- solid to liquid
Evaporation- liquid to gas
Sublimination-Solid to gas
Pure liquids vs. Non pure liquids
Pure liquids evaporate faster than non puer liquids.
Rate of evaporation
depends on the forces holding the molecules together in a liquid state
Increase temperature favors…
escape because molecules move faster
Vapor pressure
Pressure exerted by a vapor above a liquid. Lower the vapor pressure, you increase the boiling point and vice versa.
Molecules with high vapor pressure
Are volatile and evaporate easily. The higher the vapor pressure the easier it is for the liquid to evaporate. I.e- alcohol
Vapor pressures increase as temperature….
increase
Boiling
Is a special form of evaporation. Occurs when heat is added to a liquid. Evaporation doesn’t just occur, so do bubbles.
Changing boiling point.
The boiling point of a liquid is lowered as external pressure decreases; the opposite is also true.
Vacuum distillation allows one to boil water well below 100 degrees
Boiling at elevations
Pressure cookers increase pressure , and increase the boiling point. (More than 100 degrees C) Cooks at higher temperature.
The higher elevation, the lower the air pressure lower the boiling point. (Mount Everest)
The lower the elevation, the higher the air pressure and the higher the boiling point. (Death Valley)
Intermolecular forces
forces/interactions that exist between molecules
Dipole-Dipole
these are electrostatic attraction between polar molecules.Polar molecules have a partial negative end and a partial positive end.
Hydrogen Bonds
Is dipole-dipole interactions, but because Hydrogen is involved makes it an extra strong interaction. This is because H is small.
It is an attraction between a positively charged H atom, and a negatively charged O, F, or N atom in another molecule.
Hydrogen bonds are so strong, so that they decrease the vapor pressure, and increase boiling point of the liquid.
Takes a long time to boil hydrogen bonds because they have higher melting/boiling points than liquids with no hydrogen bonds.
I.E water!! Polar molecules
**Is extremely important in number of interaction between biochemical molecules such as proteins, enzymes and DNA.
London forces
Weakest of all forces
Momentary attractions due to the movement of the electron cloud between non polar molecules
I.e Cl2
These forces increase with molecular mass
Ex. Br gas is larger than Cl gas which is larger than F gas.
London forces cont.
The electrons are further away from the nucleus therefore they are polarized easier.
Larger molecules have more SA to attract to each other.
Theses are very weak interactions, but if there are many of them it can be very significant.
Solutions
Is a homogenous mixture of a solute in a solvent.
Solute is always in lesser amount
Solvent is always in greater amount.
There are 9 types based on the number of diff. phases.
Types of solutions
Gas in a gas- air. Nitrogen would be the solvent, and CO solute.
Gas in a liquid- soda. Sugar liquid is the solvent, and CO2 is the solute.
Liquid in a liquid- vinegar or rubbing alcohol. Both are mixed with water.
Solids in liquids- salt in water. Sugar in water.
Liquid in a solid- is a gel. Texture changes.
Solid in a solid- alloys, brass, or bronze (copper and silver).
****they all look as if they’re one!!!
Solubility
The maximum amount of solute that will dissolve in a given amount of solvent under a given set of conditions.
Expressed as grams per solute/ 100 g solvent.
Temp. effects for a liquid in a liquid
If you add heat, it usually increases solubility
Temp effects for a gas in a liquid
if you add heat, it decreases solubility.
Pressure effects for either a solid or liquid in a liquid
increased pressure causes little or no change in solubility.
Pressure effects on a gas in a liquid
Increasing pressure increases solubility
Henry’s Law
For a gas in a liquid, increased pressure causes increased solubility.
“The Bends”- when diving deep into water, there is increased pressure and this causes the dissolution of Nitrogen in blood.
When surfacing quickly, the nitrogen escapes from the blood and causes serious health affects.
Concentrations of solutions
Dilute solution- small amount of solute in solvent.
Concentrated solution- large amount of solute in solvent.
Saturated solution- maximum amount of solute that can be dissolved in a solvent at a given condition.
Supersaturated- Contains more solute than theoretically can be dissolved in the solvent. You can see particles.
Unsaturated-Contains less solute than can be theoretically dissolved in a solution.
Aqueous vs. non aqueous solutions
Aqueous solution- solute in water.
Non-aqueous solution- Substance other than water is the solvent
Solution formation
In a solution, solute particles are evenly dispersed.
In order to form a solution, you have to overcome and break apart forces that are holding the existing molecules together.
Then you need to reform them, new attractions must be made between solute particles and solvent particles
Ionic compounds
Metals bonding to non metals. They are interacting in such a way so that when they become ionized they form a charge, the metal loses electrons, and the non metals gain electrons. They usually form large crystal molecules.
Salt to water. Water molecules are polar, and because they’re polar, they will pull apart the Na from the Cl. Rip apart lattice. (ionization)
Forms Na ions and Cl ions.
Then the water molecules surround the ions and form a layer of hydration.
If you can’t break apart the lattice it will not be soluble in water. Most ionic compounds are soluble in water, because water is strong.
Sometimes you can add heat to increase the solubility and help with the break down.
Can be exothermic or endothermic.
Covalent bonds
Contain covalent bonds. 2 non metals. Sharing of electrons. There are no ions formed, no ionization taking place, do not exist in a crystal lattice. They are in molecular geometry.
Consider glucose- water collides with glucose molecules and hydrogen bonding occurs. If hydrogen bonding does not occur, it is NOT SOLUBLE in water. Layer of hydration forms.
Hydrogen bonds= water bonding to O, N, or Fl.
Consider glucose- Glucose has O’s and H’s.
If the C:O ratio is 3:1 or less, it is soluble in water.
Some things can react with water to become soluble. Acids do this.
Percent Concentrations for weight
FOR WEIGHT Parts per hundred
Mass of solute over mass of solution x 100.
The percentage means g of solute per 100g of solution.
Solid in a liquid. (m/v) or (g/ml). Grams plus grams does equal 100.
Percent concentrations for volume
VOLUME IS DIFF! %v/v- i.e 3% alcohol means 3% per 100 mls of water.
Pipette 3 ml of alcohol and then add water up to 100mls. Does not mean 97 ml of water plus 3 ml of alcohol.
“Take 3 ml of alcohol and qs it to 100 ml”
Volume plus volume does not equal 100.
Fluid Movement
5% glucose or 5% KCl. The solutions appear to be equal concentrations.
Will water move across this membrane?
The question cannot be answered using these concentration units.
What concentration units do you use? Molarity
Water will move to the substance with the greater osmolarity
Molarity
In the body. (M)
Number of moles of solute per liter of solution.
Units are moles per liter or millimoles per milliliters.
1M of NaCl means 1 mole of NaCl per Liter of Soln.
Remember that 1 mole is equal to molecular weight.
To make this solution put 58 grams of NaCl and bring it up to 1 Liter. To half this, use half molar mass and half a liter. 58 x .5. If you want a third? 58 x .3
Grams solute= form. mass x molarity x volume
MASS MUST BE IN GRAMS, VOLUME MUST BE IN LITERS!! You can use ml, but you have to use mg then.
Dilutions
Dilutions only involve adding solvent (water) to a solution.
Therefore the number of moles in the solution stays the same.
Since molarity= moles per liter…. Moles= liter x molarity
C1 v1 = c2v2
# of millimoles= moles x milliliters
Colloids
Not a true solution, particles are dispersed equally but not dissolved. (sand in water)
Cannot visually see the particles.
Colloidal particles scatter light (tyndall effect)
Particles can pass through filter paper
They do not settle out
Are 10 -7 to 10 – 5 cm … very small. Particles any larger than this will settle out
Colloidal dispersion
Are stabilized by:
Particle motions and collisions (Brownian movement)
Solvation layer around dispersed phase. (Similar to hydration layer)
Like charges on surface of particles (solvent and colloid)
How to make colloids unstable
To make them unstable, you can change the solvation layer (colloid will come out of the soln) or cancelling the surface charge.
Plasma proteins, and fat transport in blood, example of colloids. If you were to add fat you’d change the solvation layer.
Alcohol to blood would denature a protein, and it would precipitate out.
Collegative properties of solutions
Physical property of a solution, that depends only on the number of solute particles present in a given quantity of solvent and not on their chemical identities. I.e: water, you add some salt and water will change its physical properties.
The solute thus:
Decreases melting (freezing) point
Raises boiling point
Causes less evaporation of solvent

Examples: salt on wet roads in winter, salt in boiling water, antifreeze.

One mole of ionized vs One mole of ionized in a solution
One mole of un-ionized solute per liter of solution lowers the freezing point by 1.86 deg. C and increases the boiling point by .51 deg. C.
One mole of ionized solute per liter of solution:
Number of ions produced is important, each acts as a particle.
1 mole KCl ionizes into K and Cl (2 particles)
Multiply by number if ions.
Osmosis
Passing of water through a semi permeable membrane.
Water moves from dilute solution to more concentrated solution. (less to more)
This will stop when both sides are at equal concentration (EQ)
Osmotic Pressure
Prevents the flow of water. Prevents osmosis.
Applied to concentrated side.
Only the number of solute particles (concentration) matter for osmosis to occur.
Particles that contribute to osmosis are:
Ions (salt)
Small molecules (glucose)
Colloids (proteins)
Most biological membranes are not purely semipermeable (osmotic) They allow the passage of other small molecules.
Osmolarity
Important in predicting movement (osmosis) in physiological systems.
Osmolarity is directly proportional to its osmotic pressure.
Osmolarity= M x # of particles liberated. (for ionic compounds)
Osmolarity = M (for molecular compounds)
Isotonic fluid
Isotonic solution has the same osmotic pressure as intracellular fluid.
Hypotonic solution
Hypotonic solution has less osmotic pressure than intracellular fluid.
causes cell lysis, due to water movement in the cell.
Hypertonic solution
has a greater osmotic pressure than intracellular fluid. Causes water to leave the cell and the cell to shrink
Mg Sulfate
Increases the osmolarity of the small intestines.used in some laxative medications. This is an osmotic cathartic and draws water into the intestines.
Epsom salts
Used as a foot bath to reduce swelling
It draws water out of the foot
Dialysis
Passage of small molecules and ions (solutes) across a biological membrane.
The direction of concentration is from high to low.
Hemodialysis is used to remove waste solutes from the blood in kidney disease.
The impure blood is passed across a membrane in an isotonic solution to prevent the loss of electrolytes.
Then it is disposed of
Normal blood vessel
Allows water, Na, Cl, glucose etc. to pass to/from interstitial fluid (space between cells).
Proteins and RBCS (cells) are large enough to be colloids and cannot pass across (stay in blood), hence little protein/no blood in interstitial fluid.
If something happened, leaking could occur. High bp can cause this to occur. This increase bp or increased capillary permeability can allow these larger entities to pass across the membrane. (Think about a clogged drain)
Distribution of body water
60-70% water
50% is intracellular fluid (solid masses, cells dealing with tissues)
5% is in blood (plasma-> fluid portion of blood)
15% is interstitial fluid
Excess water equals edema.
Decreased water equals dehydration.
Normal solute levels- major contributors to Osmolarity of plasma.
Na- 140 mm/l – most important
k- 4 mm/l
Cl- 100 mm/l
HCO3- 25 mm/l
Albumin- 5 g/dl
Glucose- 90 mg/dl
Urea- 7-18 mg/dl
Osmolarity of serum
Total osmolarity of serum is 280-300 milliosmoles.
Is regulated through osmoreceptors in the hypothalamus.
Control of osmolarity depends on ADH
ADH promotes reabsorption of water in the kidney’s renal tubules.
Urine Osmolarity
Has a higher osmolarity than blood. Fluctuates greatly during the day.
Measured over 24 hours in a huge bucket. Usually greater than 600 milliosmoles per liter.
Urine to serum ration should be greater than 1.5 normally.
If it is less than 1, it means diabetes insipidus which causes large losses of water. Lack of ADH.
If it equals one, there is no concentrating ability of the kidneys. It means the kidneys are failing. Blood and water are the same.
Monitering kidney function
BUN- blood urea nitrogen. Concentration of urea in blood.
Urea is the way nitrogen is excreted. Nitrogen is toxic in the human body.
Liver removes nitrogen, converts it to urea. Urea is easily cleared by kidneys (low renal threshold).
Urea is not easily cleared by the kidneys when it has high renal threshold. They are not easily removed at high concentrations. (Glucose, Proteins-amino acids- high renal threshold). Goes in the urine when it is high in the blood and that is a problem.
Fluid balance
Intracellular fluid to Extracellular fluid (blood) to interstitial.
Water flows this way. Water could not go from intracellular to interstitial though.
They should all be at equal osmolarity (EQ) but with different solute composition.
If the fluids mix out of order, there is usually an injury.
Solutes in ECF (plasma)
Cations- major in order
Na
K
Ca
Mg
Anions-
HCO3
Cl
Proteins -(adopt anion charge, called proteinate)
Non-ionized organics- glucose, metabolic acids, urea, etc.)
Solutes in interstitial fluid (blood)
Same as ECF MINUS PROTEINS.
Proteins are too big to pass into the interstitial fluid
Solutes in ICF- inside the cell
Inside the cell
Potassium is found in the highest concentration. Also there is Mg, and Na. (cations)
Anions- HPO4 2 -, and H2PO4 –
Calcium, protein, nonionized organics and glucose are also found in cell.
Fluid movement- ICF to ECF
Water leaves the cell, it shrinks. Leads to dehydration.
Water moves from low osmolarity to high osmolarity. From dilute to more concentrated.
Blood got more concentrated, so the water moved.
Why did the blood get more concentrated?
ADH decrease, water loss.
Increased ECF osmolarity (diabetes, ketosis, hypernatremia). Produce more urine to get rid of the ketones.
Cells become dehydrated.
Fluid movement- ECF to ICF
Reverse is exactly the reverse.
Water into the cells, swelling/edema. Intracellular edema.
Decreased ECF osmolarity. All due to a solute decrease in the plasma. (hypoglycemia, and prolonged diuretic use.)
Lower blood volume, affects brain- dizzyness, double vision, shaking, etc.
Fluid movement- ECF to interstitial
In capillaries, because blood pressure is so high, it causes fluid to leak. At arterial end, blood pressure is greater than blood osmotic pressure.
At venous end, blood pressure is less than blood osmotic pressure.
Net result: At arterial end, water leaves the blood vessel (ECF) and go into interstitial. At venous end, water flows back in and maintains balance.
Causes for extracellular edema
In capillaries, because blood pressure is so high, it causes fluid to leak. At arterial end, blood pressure is greater than blood osmotic pressure.
At venous end, blood pressure is less than blood osmotic pressure.
Net result: At arterial end, water leaves the blood vessel (ECF) and go into interstitial. At venous end, water flows back in and maintains balance.
Kidneys
Decrease Bp, decrease CO, decrease of blood flow through kidneys. The kidneys don’t function properly.
Kidneys secrete renin, renin acts on Angiotensinogen to form Angiotensin I.
I is converted to II by ACE due to the lungs.
Angiotensin is a powerful vasoconstrictor which raises bp.
Increase flow of blood through kidneys. Causes adrenal cortex to produce aldosterone, a steroid which causes kidneys to reabsorb Na.
When Na increases in the blood, it increases osmolarity, causing water to go into the blood which increases blood volume/pressure.
ACE inhibitor
decrease production of angiotensin II to decrease BP. (people with high BP would take this)
Consequence of increased fluid return
The increased fluid return to an unhealthy heart causes extracellular edema.
If it’s not removed it can cause respiratory distress.
Arrhenius theory
Acids: hydrogen containing covalent compound, when in water produces an H+ ion. (Ionization) (forms a proton when added to water)
Base: A hydroxide containing ionic compound, that in water OH- is produced.(dissociation)
Bronsted Lowry Theory
Acids: substance that donates a proton (H+) to some other substance.
Base: substance that accepts a proton (H+) from another substance.
Can’t have an acid without a base.
In water H+ cannot exist in a free state, thus it reacts with water to produce hydronium ions.
pH meters measure pH3 O +, not H+
HCO3, two bonds are covalent, and one is coordinate covalent.
Conjugates
Conjugate base- the substance that has lost the proton.
Conjugate acid- the substance that gained the proton.
Amphoteric substances
Can gain or accept a proton depending on what they’re reacting to. They function as both an acid or a base, not at the same time though. Best example is water, amino acids, and bicarbonate.
Di and Triprotic acids
How many protons can it donate?
Mono- donates 1 proton
Di- donates 2 protons, undergoes 2 reactions
Tri- donates 3 protons
Strengths of Acids and Bases
Depends on the degree of ionization in water.
Strong acids ionize 100%, weak acids ionize 5%.
Strength has nothing to do with concentration.
It also depends on position of the EQ with water.
– Strong acids favor products
– Weak acids favor reactants
Strengths cont.
Strong acids, have weak conjugate bases.
Weak acids, have strong conjugate bases.
Any acid that contains carbon is a weak acid. They are organic acids.
Group 1 A bases are very strong, as well as group 2A bases. All other bases are classified as weak. 1 or 2 OH’s are strong. Any more than that is weak.
How is dialysis and osmosis different?
Osmosis only allows solvent molecules to pass through the membrane, whereas dialysis only allows solute particles to pass through the membrane.

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