Chapter 8

Chemistry

Solvent

substance present in a large amount in a solution (water in sweet tea)

Solution

Homogeneous mixture, solute is uniformly mixed with solvent (tea)

Solute

bstance present in a small amount in s solution (sugar in sweet tea)

Aqueous solution

dilute solution where water is the solvent (sweet tea)

Colloid

homogenous mixture of particles suspended in solution (particle size 1-1000nm (1um) diameter-milk)

suspension

large particles suspended in a solution, will separate over time (blood)

Solvation

solvent particles surround the solute particles and interact through attractive forces (when aqueous=hydration)

solvation by water

Ion dipole interactions

Unsaturated solution

contains less than the maximum amount of solute that can dissolve

Saturated solution

contains the maximum amount of solute that can dissolve

Effect of temperature on solubility

• Increase temperature increases solubility for most solids (movement makes space)

• Increase temperature= decrease solubility for gases (more energy=more movement=fewer IMF)

Effect of pressure on solubility gases

-Henry's Law: solubility of gas in a liquid is directly related to the pressure of that gas over the liquid

-Solubility of gas increases with increased pressure of gas over the liquid

Henry's Law applied to soda

When the can is opened, the CO2 is no longer forces into solution in the soda. Pressure in headspace of the can keeps the CO2 in solution

Strong electrolyte

complete dissociation of solute into ion when dissolved in water

Weak electrolyte

partial dissociation of a solute into ions when dissolved in water, most of the solute stays intact as the molecule

Nonelectrolyte

molecule that dissolves in water but does not dissociate into ions

Equivalent (Eq)

relates the charge in a solution to the number of ions or moles of ions present

• The number of equivalents present per mole of an ion equals the charge on that ion

• ex: (1Eq Na+/ 1mole Na+)

Mass percent (m/m)

= mass of solute(g) / mass of solute(g)=mass of solvent (g) x 100%

or

=mass of solute (g)/ mass of solution (g) x 100%

volume percent (v/v)

volume of solute/volume of solution x 100%

Mass/ volume percent (m/v)

grams of solute/ milliters of solution x100%

Molarity (M)

moles of solute/liters of solution

What is the conversion factor when given a percentage?

grams of the percent/ 100 mL

• ex: 5% = 5g/100mL

Dilution

a specific amount of solvent is added to a solution

• increases volume of the solution

• decreases the concentration of the solution (amount of solute does not change)

Dilution formula

C1V1=C2V2

** When the problem states diluted, dilution, dilute, we are working with the C1V1=C2V2

Isotonic solution

concentration of dissolved solutes is the same on both sides of the membrane

Hypotonic solution

concentratration of dissolved solutes outside of a cell is LESS than concentration inside of cell

Hypertonic solution

concentration of dissolved solutes outside of cell is greater than concentration inside of cell

What is a membrane?

The membrane is a complex combination of molecules

What do solutes do on membranes?

They can move across membranes

Diffusion: solutes moving across membranes

1. Movement of solute molecules across a semipermeable membrane

2. It's easy to move down a concentration gradient (from high to low)

3. It's hard to move up a concentration gradient (requires energy in the form of ATP)

Passive diffusion

goes from high to low concentration

Facilitated transport

need proton

Active transport

need energy to go from low to high

Osmosis

Water flows from less concentration area (dilute solution, more H2O molecules) to move concentrated area (concentrated solution, less H2O molecules) to even out the concentrations

Example with cells:

• Isotonic solution

  • the cell stays normal

• Hypotonic solution

  • the cell will swell

• Hypertonic

  • the cell will shrink

Isotonic solution

Cell stays normal

Hypotonic solution

It will swell (hemolysis)

Hypertonic solution

The cell with shrink (crenation)

Dialysis

Process for removing waste from the blood:

"Two-way street": Blood that contains too many solutes goes through the tube into the machine filled with a dialyzing solution. The tube has holes big enough for solutes to move out into the solution but not big enough for red blood cells to leave. Waste/solutes are removed from the blood, making it clean enough to move back into the body.