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Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department 1 Methods expressing Concentrations of solutions.

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Presentation on theme: "Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department 1 Methods expressing Concentrations of solutions."— Presentation transcript:

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2 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department 1 Methods expressing Concentrations of solutions

3 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department ILO of the current topic: By the end of this topic, the student will be able to: Apply different methods for expressing concentration (A) Perform different dilutions from stock solution(B).

4 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department METHODS EXPRESSING THE CONCENTRATION OF A SOLUTION ? ?

5 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology DepartmentSolutions SOLVENT= SOLVENT= material that dissolves another. SOLUTES= SOLUTES= Substance being dissolved. Most common types of solutions involves Solid dissolved in a Liquid.

6 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department

7 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Stirring Smaller pieces. Temppressure Factors determining rate of solution formation

8 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Factors determining rate of solution formation: Stirring: Stirring: moves solvent into contact with the solute. Smaller pieces Smaller pieces increase the surface area of the solute. Higher temperatures Higher temperatures make the molecules of the solvent move faster. Pressure Factor: Pressure Factor: extra pressure will not increase solubility of Solids and Liquids (already close together) **Increase pressure squeezes only gas solute into solvent.

9 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department The concentration of a solution represents the amount of solute dissolved in a unit amount of solvent or of solution.

10 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department The amount of solute in Definite volume of solvent or solution

11 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department *Concentrated *Diluted

12 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department International Units of mass and volume The basic international unit of mass is the kilogram (kg) and its fractions. The basic international unit of volume is the liter (L) and its fractions.

13 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Basic International Units 1 gram (g)= kg 1 milligram (mg)= g 1 microgram (µg)= g 1 nanogram (ng)=10 -9 g 1 picogram (pg)=

14 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department 1 Liter (L) = 1 dm 3 (cubic decimeter)= 10 3 mL 1 deciliter (dL) = L (10 -1 dm 3 )= 100 ml 1 milliliter (ml) = 1 cm 3 (cubic centimeter)= L= 1 microliter (µL) = 1mm 3 (cubic millimeter)= L Basic international units

15 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Methods Of Expression Of Concentrations

16 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Percent Concentration Describes the amount of Solute dissolved in 100 parts of solution Amount Of Solute Amount Of Solute 100 Parts Solution 100 Parts Solution.

17 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department The most commonly used two methods are according to the nature of solvent: Percent / volume Solvent Is Liquid Percent / mass Solvent Is Solid 1- Percentage (%)

18 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Further divided into 2 types according to the nature of solute: volume / volume % (V/V %) Solute Is Liquid 70% ethyl alcohol (70 ml/100ml) weight / volume % (W/V %) Solute Is Solid (Commonly used) glucose 5 mg% (5mg/100ml)

19 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department = Mass of solute (g) / Mass of solution (g) x 100% Most common e.g. Gold Alloys (with copper or silver “Solutes” )

20 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department % Mass/Mass ( سبايك الذهب و النحاس ( % Volume/Volume mL% Mass/Volume % gm %

21 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department 20 Learning Check %C-1 A solution contains 15 g Na 2 CO 3 and 235 g of H 2 O? What is the mass % of the solution? 1) 15% (m/m) Na 2 CO3 2) 6.4% (m/m) Na 2 CO 3 3) 6.0% (m/m) Na 2 CO 3

22 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department 21 Answer %C-1 Mass of solution= 15 g g = 250 g %(w/w) = 15 g Na 2 CO 3 x g solution = 6.0% Na 2 CO 3 solution

23 22 Learning Check % C-2 An IV solution is prepared by dissolving 25 g glucose in water to make total 500 mL solution. What is the (w/v %) of the glucose in the IV solution? 1.5.0% 2.20.% 3.50.%

24 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department 10% Ethanol Solution (v/v) Volume-Volume %

25 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department How much solute is present in mL of a 14.7% (mass/volume) NaCl solution? Mass/volume % = (mass solute /volume solution ) % = (x / mL ) 100 x = (756.1 mL) x = mass of solute = 111g

26 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department 2- Molarity (M) A concentration that expresses the number of moles of solute in 1 L of solution Molarity (M) = no.moles of solute 1 liter solution (It is abbreviated as a capital M “mole/L” )

27 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department The Mole is the primary SI unit of the amount of substances: Weight of 1 mole of any substance = its molecular weight (MW) in grams.

28 MW: It is the sum of the atomic weight of all atoms in the formula expressed in gram eg : one mole of NaH 2 PO (2×1) (4 × 16)= 120 g= weight of 1 mole The Basic International unit for matter

29 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Important note All solutions of the same molarity (M) in the same volume of solution= contain the same no. of solute molecules. = Avogadro´s number N = x particles in 1 mole

30 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department In mathematical equations, the molar concentration is expressed by using the brackets [ ] 1 mole= 1000 mmole 1 millimole (mmole)= mole 1 micromole (µmole)= mole

31 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Is a solution that contains one mole of a specified matter. of a specified matter per liter. 1M =1 mole/L e.g. e.g. 2 M solution of Ca =80 g/L as the molecular weight of Ca= 40g

32 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Prepare one Molar solution of NaCl [Na = 23 + Cl = 35.5] in 1 L solution 1 M NaCl = 58.5 gm/L

33 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Prepare 0.25 M solution of NaCl i.e. 1/4 M concentration = 58.5/4 g NaCl = g /L solution

34 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Using 16 g NaOH, 200 ml solution is prepared. Which ones of the following statements are true for this solution? (Molar mass of NaOH is 40 g). A.Concentration of solution is 2 molar B.Volume of the water in solution is 200 ml C.If we add water to solution, no. Of moles of solute decrease.

35 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department I. Calculation of Moles of NaOH: 40g NaOH = 1mole, so 16 g NaOH =?? mole = 16/40 =0.4 mole; V = 200 mL= 0.2 Liters So, Molarity = 0.4/0.2=2 molar. ………… A is true

36 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Lab activities

37 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Prepare a 0.5 M solution

38 FINALLY GET STARTED WITH YOUR ACTIVITIES

39 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department 38 Methods expressing Concentrations of solutions

40 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department ILO of the current topic: By the end of this topic, the student will be able to: Apply different methods for expressing concentration Perform different dilutions from stock solution.

41 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department The number of gram-equivalents of solute in one liter of solution. A normal solution contains 1 gram- equivalent weight of solute in a liter of solution. 3- Normality (N) gm equivalent / L

42 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department A gram equivalent weight (G.E.W.) of an acid or a base is the molecular weight in grams of the solute required to react, or replace one mole of H + or OH -. 1 mole of Na +1 = (1 N). 1mole of Ca +2 = (2 N).

43 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Weight of A gram-equivalent (G.E.W) of an element Weight of A gram-equivalent (G.E.W) of an element = = MW of the solute in gram (1mole) / Valency which is the number of replaceable hydrogen or hydroxyl ions. Weight of 1 G.E.W= Molecular weight Valency

44 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department 1N solution = a solution contains 1G.E.W/ L.

45 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Monovalent acids or bases HCL - NaOH- Nitric 1M = IN Divalent acids H 2 SO 4 1M = 2N Trivalent acids Orthophosphoric acid 1M = 3N

46 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Normality = Molarity x Valency Normality of 1M H 2 SO 4 = 1 x 2 = 2 GEW/L Normality of 1M HCl = 1 x 1 = 1 GEW/L Normality of 1M H 3 PO4 = 1 x 3 = 3 GEW/L Normality of 0.4M H 3 PO 4 = 0.4 x 3 = 1.2 GEW/L Normality of 0.2M NaOH = 0.2 x 1 = 0.2 GEW/L

47 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Prepare 1 normal solution of NaCl [MW of Na= 23 & of Cl = 35.5] MW of NaCl= = 58.5 g G. E. W. = 58.5g Thus, a solution of 1N NaCl contains 58.5 g of NaCl / 1 L.

48 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Prepare 1 normal solution of CaCl 2 [MW of Ca= 40 +Cl = Cl = 35.5] MW of CaCl 2 = = 110g G. E. W. = 110g/2=55 Thus, a solution of 1N CaCl 2 contains 55 g of CaCl 2 / 1 L.

49 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department (c) What is the normality (N) of 0.3 M orthophosphoric acid? Normality = Molarity x Valency 0.3 x 3 = 0.9 N

50 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department To convert between gram and mole we have to know the MW Mole= Weight (g) MW (g) To convert between M and N, we have to know the valency. Normal= Molarity x valency

51 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department What is the plasma urea concentration in mmol/L corresponding to 20 mg/dL? (m.w. of urea = 60) Solution : Conc. of urea in mmol /L = 20/60 = mmol/dl x 10 = 3.33 mmol/L

52 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department What is the plasma sodium (Na+) concentration in mmol/L (mM) corresponding to 140 mEq/L (mN)? Solution: Conc. of (Na+) = 140 mmol/L

53 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Summary

54 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Expressing concentrations in parts per million (ppm) requires the unit on top to be 1,000,000 times smaller than the unit on the bottom. It is used to measure trace substances in solutions or mixtures, eg. mg/kg, µg/g. Cl Concentration in swimming pools.

55 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department You dilute a solution whenever you add solvent to a solution. Adding solvent results in a solution of lower concentration.

56 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department You can calculate the concentration of a solution following a dilution by applying this equation: C i V i = C f V f Where: C =concentration, V = volume i =initial value. f =final value.

57 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Is the ratio of the original volume to the final volume. If 10 ml of blood are completed to 100 ml with saline, we say that blood is diluted 1 in 10, and the dilution factor is 100 / 10 = 10 The dilution factor = Final volume / original volume

58 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department How many milliliters of 5.5 M NaOH are needed to prepare 300 mL of 1.2 M NaOH? Solution: 5.5 M x V i = 1.2 M x 0.3 L V i = 1.2 M x 0.3 L / 5.5 M V i = L= 65 mL So, to prepare the 1.2 M NaOH solution, you add 65 mL of 5.5 M NaOH into your container and add water to get 300 mL final volume. So, to prepare the 1.2 M NaOH solution, you add 65 mL of 5.5 M NaOH into your container and add water to get 300 mL final volume.

59 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department UnitsSymbolDefinition Mass Percent% m/m Mass Solute/Mass solution x 100 Volume Percent% v/v Volume Solute/Volume solution x 100 Mass / Volume Percent % m/v Mass Solute/Volume solution x 100% MolarityM Moles solute/L solution NormalityN Gram equivalent/L solution Part per millionppm Summary of Concentration Summary of Concentration units

60 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department Lab activities

61 Faculty of Medicine Ain Shams University Medical Biochemistry & Molecular Biology Department - Prepare a 0.5 M solution - Dilute the 0.5 M solution to 0.25 M

62 V 1 × C 1 = V 2 × C 2 N = M × V M = moles / liter G E W= MW/V

63 Thank You


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