II.WEEK
2nd WEEK
BIOCHEMICAL SOLUTIONS
Preparation of solution
% Solutions, molar solutions, normal solutions,
osmolar solutions, isotonic solutions, molal solutions,
ppm solutions
BIOCHEMICAL SOLUTIONS
Definition:
Homogeneous mixtures of two or more
substances are called solutions. More than
the amount of the solvent, the less the
solute.
Cautions When Preparing Solutions:
• The required solids and chemicals should be pure and clean, and the glass materials used should also be clear and clean.
• Suitable weighing containers should be used during weighing. If necessary, the weighing container should be washed with a small amount of solvent.
• If a solid substance is to be dissolved in a liquid solvent, first dissolve it with a small amount of solvent; The final volume should be completed after the desired volume.
• If strong acid or base is to be used, water should be added to the acid or base.
Information on chemical substances should be observed.
• Each solution should be kept in suitable conditions (temperature, humidity, light, darkness, etc.) If not stated otherwise, the solution will be stored in the refrigerator.
Concentration
The amount of substance in the volume or mass of the solution is called concentration. Main concentration units; molarity (M), normality (N), molality (m), percentage concentration (%) and osmolarity.
Standard Solution
The solvent and the amount of the solute in the solution are well known solutions.
1) The concentration of the substance should remain constant for a long time.
2) Soluble and solvent should be mixed in a short time.
3) The solute should be completely dissolved in the solvent.
http://2012books.lardbucket.org/books/principles-of-general-chemistry-v1.0/s08-02-solution-concentrations.html
% Solutions
The molecular weight of the solvent or solvent does not need to be known.
Percent concentration (%) refers to the amount of substance present in 100 ml or 100 g of solution.
-Weight/Weight (w/w): Amount of grams in grams per 100 g of solution
-Volume/Volume (v/v): Amount of volume of dissolved substance in 100 ml of solution (ml)
-Weight/Volume (w/v): The amount of solute in 100 ml of solution in grams (g)
Important reminders
- If the solvent is not specified, distilled water should be understood.
- The final volume is important when preparing the solution.
For example, when preparing 100 g/L (w/v) solution, if you add 1 L of solvent over 100 g of solute, the calculation is incorrect because the final volume will be more than 1 L.
Molar Solutions
It is the mole amount of the substance dissolved in oıne liter.
M = N / V; n = moles of solute, V = volume of solution
Example: How to prepare 0.2 M NaCl solution? (Na: 23, cL: 35.5) 0.2 M = n / 1 L if n = 0.2 mole.
If n = m / Ma, 0.2x58.5 = 11.7 g NaCl is weighed and the final volume is 1 L and 0.2 M NaCl solution is obtained.
Normal Solutions
It contains solutions with 1 equivalent grams per liter. In order to calculate the normality, the equivalent weight of the substance and its amount in solution should be determined. The equivalent gram of a substance is calculated by dividing the molecular weight of that substance by the effect valance.
Equivalent weight = molecular weight/effect valence
Effect valence for; acid: number of H+
base: number of OH-
salts: number of positive charges in the compound
reduction oxidation reactions: they are equal to the number of electrons.
1 equivalent grams of NaOH; 40/1 = 40 g
The link between normality and molarity; Normality = Molarity x effect valence
Isotonic solutions
Solutions containing the same number of osmotically active particles having the same osmotic pressure are called isotonic solutions. There is an isotonicity between these solutions if a solution has an osmotic active particle equal to another solution, that is, osmotic pressure. In the biochemistry, the solution having the same osmotic pressure as the plasma is understood when the isotonic solution is mentioned.
Molal Solutions
The solution obtained by dissolving 1 mole of substance in 1000 g of solvent is called a molal solution.
Molality (m) = number of moles of solute/1000 g of solvent Osmolar Solutions
Osmolarity is the amount of osmol grams dissolved in 1 L solvent. It is indicated by Osm.
1 osmol gram = molecular weight/osmotically active particle.
For example; NaCl decomposes completely into Na and Cl ions in aqueous solution. Since each molecule forms two osmotically active particles, 1 osmol grams NaCl 58.5 / 2 = 29.25 grams. In other words, there are 29.25 g of NaCl per liter of 1 osmolar NaCl solution. 1 osmolar glucose is 180 grams. Because glucose is dissolved in the molecular form and 1 active particles.
