Solutions PDF

4 solutions solutions Solutions are homogenous/uniform mixture of 2 or more substance based on Composition: solute A compound of a solution that is present in lesser quantity than the solvent solvent The solution component present in the larget quantity based on solubi...

4 solutions solutions Solutions are homogenous/uniform mixture of 2 or more substance based on Composition: solute A compound of a solution that is present in lesser quantity than the solvent solvent The solution component present in the larget quantity based on solubility unsaturated solution A solution that contains less solute than it can hold at a given temperature. saturated solution A solution that contains the maximum amount of solute that can be dissolved at a given temperature. supersaturated solution A solution that contains more solute than it can normally hold at a given temperature. It is an unstable state. factors affecting solubility Difference in polarity The greater the difference, the less soluble is the solute Nature ot solute and solvent “like dissolves like” SATURATION POINT Maximum amount of solute expressed in grams that can be dissolved in 100g if water MISCIBILITY Ability of one substance to mix with another substance (eg. liquid-liquid) factors affecting solubility temperature Increase in temperature usually increases the solubility ENDOTHERMIC increase in temperature = increase in solubility EXOTHERMIC Increase in temperature = decrease in solubility factors affecting solubility pressure GASES As pressure increases, the solubility of a gas in a liquid also increases. LIQUIDS AND SOLIDS Pressure has a negligible effect on the solubility of liquids and solids. factors affecting solubility PARTICLE SIZE AND SURFACE AREA DECREASE in particle size = INCREASE in solubility INCREASE Surface area = INCREASE in solubility factors affecting solubility presence of salt salting-out salting-in Presence of salt, decreases solubility Presence of salt, increases solubility Alcohol + NaCl ---> NaCl + Alcohol Protein + NaCl --> Protein-NaCl + NaCl methods of expressing concentration of solutions Percent solution/Percentage composition % by mass % by volume % by mass/volume ppm (parts per million) proof Mole (n) = Mole fraction (X) = methods of expressing concentration of solutions Percentage strength For solutions or liquid preparations expressed as Percent weight-in-volume (%w/v) Percent volume-in-volume (%v/v) Percent weight-in-weight (%w/w) percent weight-in-volume (%w/v) mass of solute (g) % w/v = x 100 volume of solvent (mL) percent volume-in-volume (%w/v) volume of solute (mL) % w/v = x 100 volume of solvent (mL) percent weight-in-weight (%w/w) mass of solute (g) % w/v = x 100 mass of solute (g) + mass of solvent (g) Proof strength Expressed by taking 50% alcohol or proof spirit as 100 proof Always numerically twice as great as percentage strength (v/v) 100% or absolute alcohol is 200 proof 25% alcohol is 50 proof proof gallon Used to measure or evaluate alcohol of given quantities and strengths for purpose of taxation 1 wine gallon of 100 proof or 50% v/v wine gallon x strength of soln Proof gallon = 50% parts per million (ppm) Parts per 1 million parts Used to express concentration of dilute solutions Used to designate test limits Limit of Arsenic in znO is 6ppm or 0.0006% proof gallon Used to measure or evaluate alcohol of given quantities and strengths for purpose of taxation 1 wine gallon of 100 proof or 50% v/v PPM = mg/L Mole (N) A mole is a unit of measurement used in chemistry to count the number of particles (atoms, molecules, ions, etc.) in a substance. AVOGADRO’S NUMBER One mole contains exactly 6.02214076 × 10²³ particles. weight of substance (g) Mole (n) = Molecular Weight (g/mol) methods of expressing concentration of solutions Normality The normality of a solution expresses the number of gram equivalent weights (GEW) of the solute in 1000mL of the solution mole x f (factor) N= FACTOR: L With respect to acids, the equivalent weight (EW) is the amount of acid that can furnish 1.008g hydrogen ion or With respect to bases, the EW is the amouunt of base that can furnish 17.008g of hydroxide N=Mxf Salts, Total positive ionic charge Colligative properties Collogative properties are solution properties that depend on the amount of the solute particles, rather than the identity of the solute vapor pressure lowering Addition of a non-volatile solute lowers the escaping tendency (vapor pressure of the solvent  raoult’s law When a solute is added to a solvent, the vapour pressure of the solvent decreases in proportion to the concentration of the solute o P = P (Xsolute ) WHERE: P Change in vapor pressure o P vapor pressure of pure solvent (X solute ) mole fraction of solute  boiling point Temperature at which the vapor pressure of the liquid becomes equal to the external atmosphere. VP = AP boiling point ELEVATION Tb change in boiling point Kb ebullioscopic constant or the molal elevation constant (water: Kb = 0.512C/m) Tb = Kb (m)i m molality of solution i Van’t Hoff Factor FREEZING POINT DEPRESSION Presence of salt or solute will cause lowering of freezing point Eg Ice cream making Tf = Kf (m) Tf change in boiling point Kf cryoscopic constant or the molal depression constant (water: Kf=1.86C/m) m molality of solution  osmotic pressure OSMOSIS Osmosis is the movement of solvent from a dilute solution to a more concentrated solution through a semi-permeable membrane OSMOTIC PRESSURE Applied pressure to stop the movement of solvent Cliinical Correlation: = MRTi Isotonicity Hypertonicity Where: Hypotonicity pi = osmotic pressure in atom M = molarity of solution R = molar gas constant T = temperature i = Van’t Hoff Factor gas laws Kinetic Molecular Theory of Gases: Constant, random motion Distance of separation is very large No attractive or repulsive forces exist between Collide without losing energy KE = temperature gas laws Gases are made up of small atoms or molecules that are in constant, random motion The distance of separation among these atoms or molecules is very large in comparison to the size of the individual atoms or molecules All of the atoms and molecules behave independently. No attractive forces exist between atoms or molecules in a gas. Atoms and molecules collide with each other and with the walls of the container without losing energy. The energy is transferred from one atom or molecule to another The average kinetic energy of the atoms or molecules increases or decreases in proportion to absolute temperature gas laws ROBERT BOYLE P1 V1 = P2 V2 JACQUES CHARLES V1 / T1 = V2 / T2 JOSEPH-GAY LUSSAC P1 / T1 = P2 / T2 AMADEO AVOGADRO V1 / n1 = V2 / n2 JOSEPH-GAY LUSSAC P1 V1 / T1 = P2 V2 / T2 EMILE CLAPEYRON PV = nRT boyle’s law aka Mariotte Law Relationship of pressure and volume at constant temperature Inversely proportional P1 V1 = P2 V2 CHARLES’ LAW Relationship of volume and temperature at constant pressure Directly proportional V1 V2 = T1 T2 gay-lusac’s law aka Amonton’s Law Relationship of temperature and pressure at constant volume Directly proportional (increase temperature = increase pressure) P1 P2 = T1 T2 COMBINED GAS LAW Provides convenient expression for performing gas law calculations involving the most common variable: Pressure, Volume and Temperature P1 V1 P2 V2 = T1 T2 AVOGADRO’S LAW Gases of equal volumes at the same temperature and pressure contain the same number of molecules Volume of a gas maintained at constant temperature and pressure is directly proportional to the number of moles of the gas V1 V2 = n1 n2 dalton’s law of partial pressure Total pressure is equal to the sum of partial pressure of each gas If each gas obeys the ideal gas law, then; n1RT n2RT n3RT P1 = P2 = P3 = V V V amagat’s law of partial volumes Total volume is equal to the sum of partial volume of each gas Vt = V1 + V2 + V3 + V4... GRAHAM’S LAW OF EFFUSION States that the rate of diffusion of the gas and the speed of the gas are inversely proportional to the square root of their density V1 M2 WHERE = V is velocity of molecules V2 M1 M is molecular mass of the molecules