SOLUTION

colligative

properties

and

electrolyte

Solution: Homogen mixture consists of two or more compound

Solute: compound which is diluted in solution (amount is smaller)

Solvent: compound that dilutes solut

solute + solvent Solution

(minor) (major) (homogen)

Solution and thermodynamics

Concentration

Percentage

– % weight: g compound in 100.0 g solution (w/w)

– % volume : mL in 100.0 mL solution (v/v)

– % weight/volume : g in 100.0 mL solution (w/v)

Concentration expressions

• Molarity (M)• Normality (N)• Molality (m)• Mole fraction• Mole percent• Percent by weight (% w/w)• Percent by volume (% v/v)• Percent weight in volume (% w/v)• Milligrams per deciliter (mg/dL)• Osmolality (mOsmol/kg)• Osmolarity (mOsmol/L)

• MOLARITY : mol / liter solvent

• MOLALITY: mol solut / kg solvent

• ppm : part in a million solvent

• ppb: part solut in 109 solvent

• mol fraction: ratio of mol compound to overall mol

Colligative properties

• Increase of boiling point ( ΔTb)

• Decrease of freezing point ( ΔTf)

• Osmotic pressure ( π )

• Decrease of vapor pressure (Δp)

.

Increase of boiling point and

decrease of freezing point

TASK

1.

(A)Determine molality of solut with freezing

point 0.450 oC? Kf = 1,86

(B)If this solution was made by diluting

2.12 g X in 48.92 g H2O. Count Molecular

weight of X compounds

2. The quantity of 42.5 g sucrose is

dissolved in 316 g of water. MW =342.3 g

mol-1 Kb = 0.51 Km -1 Kf = 1,86

(A) Calculate the boiling point

(B) Calculate the freezing point

Osmotic pressure

Van’t Hoff

π= c R T

π= osmosis pressure

c = concentration

R = gas constant

0.08206

L atm mol-1K-1

T = absolute

temperature

Task

A Pharmacist dilutes 2.04 gram

haemoglobin in 100.0 mL. Osmotic

pressure is 5.83 mmHg at 22.5 oC.

Determine the massa molar of

haemoglobin?

Decrease of vapor pressure

• Raoult Law

pio : vapor pressure of the pure component

xi : the mole fraction of the component in solution

Task: at 25°C the vapor pressure of pure benzene

is 0,1252 atm. 6,40 g naphtalena(C10H8) is diluted in

78.0 g benzene(C6H6). Determine vapor pressure

benzene in solution

pH

• H2O has electrolyte characteristic, meaningwater can be ionized to release ion H+ danion OH-

• If water dilute in acid, acid will release ion H+

• If water dilute in base, base will release ionOH-

• Amount of [H+] in solution is used to statebase, acid or neutral.

Acid-Base Concept

17

Concept Acid Base neutralitation

Arrhenius increase the

concentration of H+

ions

increase the

concentration of OH-

ions

H+ + OH-

H2O

Brönsted Lowry donate a proton accept a proton Transfer of proton

Lewis electron pair acceptor. electron pair donor. covalen coordination

bonding

Dipol moment

• Electricity : in connection with natural

character of dynamical charge(for example

electron flow).

• In resting time, it called electrostatics.

For two charge separated by ( r ) the potential energy will be developed by Coulomb Law

U(r) = (q1.q2) / (4pe0r)

q1 and q2 coulomb (C); r metere0 (constant) = 8.854 x 10–12 C2/Nm2

Classification of aqueous solution system

Dispersion based on particle size of solute• True solution

a mixture of two or more components that form a homogeneous molecular or ionic dispersion

• Colloidal dispersiona homogeneous or heterogeneous mixture of two or more componentsin which the solute has a larger particle size

• Coarse dispersiona heterogeneous mixture of two or more components; particle are not individual molecules or ions but are aggregates of molecules or ions

Solution as ideal or real based on thermodynamics

• Ideal solutionsolutions for which there is no change

in the physical properties of thecomponents when they are mixed

• Real solutionsolutions for which changes in the

physical properties of solution occurwhen the components are mixed

Mixture of alcohol and water is an example

of non ideal solution

• the mixture gets warm, heat is given off.

• the final volume of the solutionis less than that of the sum of

the two components.• Raoult’s law is not linear

Type ofsolutionsystem

Approx.particle sizeof solute

Microscopevisibility Filter limit Diffusion

True solution Under 10Å None None Rapid

Colloidaldispersion

10Å – 5000Å1 mm – 0.5 m

Visible inelectronmicroscope

Passed throughfilter paper, notthrough semi-permeablemembrane

Slow

Coarsedispersion

Over 0.5 m Visible withlight andelectronmicroscope

Passed throughfilter paper, notthrough semi-permeablemembrane

Slow

Dispersions of solute

• An electrolyte is a substance (an acid, a base, or a salt), that inaqueous solution ionized to positive ions (cations) and negative ions (anions).

• Electrolyte properties in aqueous solution:» exhibit anomalous colligative properties compared with non-

electrolyte» can conduct an electric current» tend to show rapid chemical reactions compared with non-

electrolyte solution

Classification of electrolytes:• Strong electrolytes

completely ionized in waterdegree of ionization is pH-independent

• Weak electrolytes

ionized only partly in water

1. acid-strong acid (acid halogen, HNO3, H2SO4 )

2. base-strong base( alkaline base, Sr(OH)2, Ba(OH)2 )

3. All salts is strong electrolyte

4. Reaktion works fully

Strong electrolyte

Weak electrolyte

1. Other acids–acid acid-weak acid.

2. Other bases is base-weak base.

3. Salts which belong to weak electrolyte is mercuri salt(II)

4. Reaction is in equilibrium (electrolyte partly ionized).

• For non electrolytes

[(g/L)/MW] × 1000 = mOsmol/L

• For strong electrolytes

[(g/L)/MW] × (number of ions) × 1000 = mOsmol/L

• For any ions

[(g ion/L)/(ionic weight)] × 1000 = mOsmol/L

Osmolarity calculation

From %w/v:

mOsmol/L = [(g/L)/(MW)] × (number of ions) × 1000

TASK(1) osmolarity of 0.9% NaCl (MW 58.45)

(1) osmolarity of 5% dextrose (D5W); (MWdextrose = 198.17)

Pharmaceutical solutionsPharmaceutical solutions---------------------------------------------------------------------------Classification Characteristics

---------------------------------------------------------------------------Oral solution Taken by mouth, inactive for flavor and (elixir, syrup) viscosity, water usual solvent

Topical solution Application to skin or mucous membranes,aqueous or alcoholic

Otic solution For the ear; usually not aqueous; glycerin,(aural) propylene glycol, and polyethylene glycol

Ophthalmic For use in the eye, inactive for viscosity,solutions free of particulates, isotonic, sterile

Parenteral For injection iv, im, or sq; few if any aqueoussolutions inactive; rigid standards for sterility; free of

particulates; free of pyrogens; isotonic;immediate effect

---------------------------------------------------------------------------

Advantages of solution as dosage form:• faster onset of activity• good for children and the elderly• homogeneous• always uniform• flexible dosing• given by any route of administration

Disadvantages of solution as dosage form:• bulk• liquid that is inconvenient• leakage from container• less stability than solid dosage forms• more pronounced taste

Type ofsolutionsystem

Approx.particle sizeof solute

Microscopevisibility Filter limit Diffusion

True solution Under 10Å None None Rapid

Colloidaldispersion

10Å – 5000Å1 mm – 0.5 m

Visible inelectronmicroscope

Passed throughfilter paper, notthrough semi-permeablemembrane

Slow

Coarsedispersion

Over 0.5 m Visible withlight andelectronmicroscope

Passed throughfilter paper, notthrough semi-permeablemembrane

Slow

Dispersions of solute

Solutions ofnon-electrolyles

Solutions ofstrong electrolytes

In nonaqueous media• behave as ideal solution

E.g. sugar, alcohols,acetamide, acetone,glyceron

Characteristics of each type of solute

Solutions ofweak electrolytes

In aqueous media• do not conduct current• no ion present• exhibit regular colligative

properties

In nonaqueous media• form ion pairs

E.g. mineral acids, strongbases, all salts: HCl,NaCl, KOH, KCl, KAc

In aqueous media• conduct strong current• totally ionized• exhibit irregular

colligative properties(based on the number

of ions)

In nonaqueous media• behave as ideal solution

E.g. weak acids, weakbases: HOAc, NH4OH,benzoic acid, atropine

In aqueous media• conduct weak current• partially ionized• exhibit irregular

colligative properties(based on the number

of ions)