1. Methods expressing Concentrations of solutionsBy
All Staff Members of
Medical Biochemistry Department

2. Apply different methods for expressing concentration
By the end of this topic, the student will be able to:
Apply different methods for expressing concentration

3. METHODS EXPRESSING THE CONCENTRATION OF A SOLUTION?
Solution
Concentration ?

4. Solid dissolved in a Liquid.
Solutions
SOLVENT= material that dissolves another .
SOLUTES = Substance being dissolved.
Most common types of solutions involves
Solid dissolved in a Liquid.

5. Factors determining rate of solution formation
Stirring
Smaller pieces.
Temperature
Pressure

6. Factors determining rate of solution formation
Stirring:moves solvent into contact with the solute.
Smaller pieces increase the surface area of the solute.
Higher temperatures make the molecules of the solvent move faster.
Pressure Factor: extra pressure will not increase solubility of Solids and Liquids (already close together)
Increase pressure squeezes only gas solute into solvent.

7. The concentration of a solution
Qualitative Expressions of Concentration
Quantitative Expressions of Concentration
Represents the amount of solute dissolved in a unit amount of solvent or of solution.

8. The amount of solute in Concentration Definite volume
of solvent or solution

9. I. Qualitative Expressions of Concentration
Diluted
Concentrated

10. II. Quantitative Expressions of Concentration
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 .

11. Basic International Units
MASS
1 kg = 1000 gram
1 g = 1000 milligram
1 mg = 1000 microgram
1 µg = 1000 nanogram
1 ng = 1000 picogram

12. Basic international units
VOLUME
1 Liter (L) = 1000 mL = 10 dL
1 deciliter (dL) = 100 ml
1 milliliter (ml) = 10-3 L = 1000 µL
1 microliter (µL) = 10-6 L

13. Methods Of Expression Of Concentrations
Percentages%
Molar concentrations (M)
Normality (N)
Very low concentrations

14. Percent Concentration
Describes the amount of Solute dissolved in 100 parts of solution
Amount Of Solute
100 Parts Solution.

15. 1- Percentage (%) Solvent
The most commonly used two methods are according to the nature of solvent:
Solvent
Percent / volume
Solvent Is Liquid
Percent / mass
Solvent Is Solid

16. A- Percent / volume V/V % and W/V %
Further divided into 2 types according to the nature of solute:
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)

17. B. Percent / mass (W/W) %
= Mass of solute (g) / Mass of solution (g) x 100%
Most common e.g. Gold Alloys (with copper or silver “Solutes”)

18. Percent Concentrationa
%Mass/mass
(سبايك الذهب و النحاس(
%Volume/volume
mL%
Mass/volume%
g %

19. Problem 2) 6.4% (m/m) Na2CO3 3) 6.0% (m/m) Na2CO3
A solution contains 15 g Na2CO3 and 235 g of H2O? What is the mass % of the solution?
1) 15% (m/m) Na2CO3
2) 6.4% (m/m) Na2CO3
3) 6.0% (m/m) Na2CO3

20. Answer Mass of solution = 15 g + 235 g = 250 g
%(w/w) = 15 g Na2CO3 x g solution
= 6.0% Na2CO3 solution

21. Problem 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?
5.0%
20.%
50.%

22. Mass/volume % = (masssolute/volumesolution) 100
How much solute is present in mL of a 14.7% (mass/volume) NaCl solution?
Mass/volume % = (masssolute/volumesolution) 100
14.7 % = (x / mL ) 100
x = (756.1 mL)
x = mass of solute = 111g

23. number of moles of solute in 1 L of solution
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”)

24. Mole 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.

25. 23 + (2×1) + 31 + (4 × 16)= 120 g= weight of 1 mole
MW: It is the sum of the atomic weight of all atoms in the formula expressed in gram
eg : one mole of NaH2PO4
23 + (2×1) (4 × 16)= 120 g= weight of 1 mole
mole
The Basic International
unit for matter

26. 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 1023 particles in 1 mole

27. In mathematical equations,
the molar concentration
is expressed by using the brackets [ ]
1 mole= 1000 mmole
1 millimole (mmole)= 10-3 mole
1 micromole (µmole)= 10-6 mole

28. Is a solution that contains one mole of a specified matter per liter.
One Molar solution
Is a solution that contains one mole
of a specified matter per liter.
1M =1 mole/L
e.g. 2 M solution of Ca =80 g/L
as the molecular weight of Ca= 40g

29. Prepare one Molar solution of NaCl [NaCl =58.5]
Weighing 58.5 g of NaCl and dissolve it in DW to final volume one litre

30. Prepare 0.25 M solution of NaCl
Answer :
1/4 M concentration = 58.5/4 g
Weighing g of NaCl and dissolve it in DW to final volume one litre

31. Using 16 g NaOH, 200 ml solution is prepared.
Which one of the followings is true for this solution? (NaOH = 40 g).
Concentration of solution is 2 molar
Volume of the water in solution is 200 ml
If we add water to solution, no. Of moles of solute decrease.

32. Answer 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

33. Prepare 100 ml of 0.5 M NaCl solution.
Lab activity
Prepare 100 ml of 0.5 M NaCl solution.
[NaCl =58.5]

35. Extended Modular Program