QUANTITATIVE ANALYTICAL CHEMISTRY PRACTICES

• Quantitative analysis methods are analytical methods based on quantitative determinations of the

substance. Today, many methods for quantification are known. In practical studies, the structural

properties of the material to be quantified are determined; sensitivity, accuracy, reliability, ease of

implementation and cost-effectiveness are factors in selecting any of these methods. Volumetric

and instrumental analysis methods will be used in laboratory studies to quantify.

Qualitative Analysis Quantitative Analysis

Analyzes to determine the qualities of the

components in the sample

Analysis to determine the quantities of the

components in the sample.

Analysis Methods

Classical Methods Instrumental Methods

If the analysis is carried out solely using solu- tions of

chemical substances, this is called as classical analysis.

- Gravimetric analysis

- Volumetric analysis

If the analysis is performed using a device, these

methods are called instrumental analysis.

- Spectroscopic analysis

- Electrochemical analysis

- Chromatographic analysis

Sample: A representative part taken to be analyzed from a material (sample).

Analytical: the component to be analyzed in a sample.

Molarity: number of moles per liter

Normality: the number of equivalents in liter

Ppm: solids content in grams per 1 kg solvent (parts per million)

Density: mass of matter per unit volume

VOLUMETRIC ANALYSIS

Volumetric analysis is a quantitative analysis method based on the measurement of the volume of a

solution of known concentration in a reaction with the analyte.

the volumetric analysis is based on the fact that the base materials react with the same equivalent

grams. for example;

A + B AB

according to the reaction equation, n equivalent grams of substance A and n equivalent grams of B

substance reacted for the AB substance. To find the equivalent grams of the substance, it is

necessary to divide the molar weight of the substance by the influence value.

INTRODUCTION TO VOLUMETRIC ANALYSISCALCULATION

Solution of A with V mL, whose normalitiy is unknown, is reacted with B whose normality is

known NB .

A + B AB

In the above reaction, You can calculate the normality of A solution.

According to this reaction the number of meq (milligram equivalent grams) of B,

NB x VB =meqB

The same number of meq A will be int he reaction

NA x VA =meqA

In equivalance point, meqB=meqA

From here you can calculate NA by NA x VA = NB x VB

In quantitative analysis, a solution of unknown normality is often given. We are asked to find the

concentration of this solution as g / L. This is calculated as follows.

C (g/L) = N x MWT (equivalent)

Standard solutions

Standard solutions are solutions in which the molarity which can be quantitatively reacted with the

substance to be determined, is definite.

For example, if a base solution is to be determined for its concentration, an acid solution can be

used as standard solution.

The standard solution can be prepared by precisely weighing the required amount of reagent.

The precise concentration of the standard solution, the reaction result of the reaction with this

substance and the solution that is precisely weighed (primer standard substance) is calculated.

Primary standard

A primary standard is a highly purified compound that serves as a reference material in volumetric and mass

titrimetric methods. The accuracy of a method is critically dependent on the properties of this compound. Important

requirements for a primary standard are the following:

1. High purity. Established methods for confirming purity should be available.

2. Atmospheric stability.

3. Absence of hydrate water so that the composition of the solid does not change with variations in humidity.

4. Modest cost.

5. Reasonable solubility in the titration medium.

6. Reasonably large molar mass so that the relative error associated with weighing the standard is minimized.

CHARACTERISTICS OF QUANTITATIVE REACTION

1) Reaction Must Be Specific And Unique

2) Reaction Must Come In An order

3) The Reaction Must Be Fast

4) The Result Of The Reaction Should Be Determined

5) The Reaction Must Be Repeatable And The Same End Result

GLASS MATERIALS USED TO BE USED IN QUANTITATIVE ANALYTICAL CHEMISTRY

PRACTICES

VOLUMETRİC FLASK: (Balonjoje) glass measuring vessel used to prepare a certain volume of

solution. There is a marking line on the neck that indicates the volume.

BURET: is a gauge glass container with a graduated pipe shape used to measure the volume of the liquid.

The burette is used for measuring the amount of the adjusted solution used in the titrimetric analysis and

for liquid transfer such as pipettes. There is a tap at the bottom end to discharge the liquid inside. In the

market there are burettes with volume between 10 - 100 ml.

DESICATOR: they are used to keep the materials which are not desiccated from the air.

GRADUATED CYLİNDER: glass containers used for liquid transfer. Not very sensitive, it is graduated

cups to take a certain volume of solution

PIPET: the tube used to transfer liquid in a known volume is glass shaped containers. There are two types of pipettes.

Single-marked pipettes and graduated pipettes.

Single-mark pipettes (transfer pipette, volumetric pipette), single marking on the volume

They are used to transfer a constant volume of liquid. They allow fluid to be delivered in the correct volume relative

to the graduated pipettes. Burets should be preferred when transferring large volume fluids from 25 ml.

Graduated pipettes allow for transfer of the desired volume of liquid to the maximum rated capacity since they are

graded.

They are called glass jugs, burette and pipettes measuring glass vessels whose volumes are precisely adjusted.

Preparation of 1L 0.1N HCl solution

From HCl stock solution, 37% purity, d= 1.19 g/cm3

M=dxV

The weight of concentrated HCl of 1000 mL is

M= 1.19 x1000= 1190 gr.

In 100 g 37 g HCl is pure

In 1190 g x X= 440.3 g pure HCl

1 N 1L HCl 36.5 g HCl required

0.1 N 1L 3.65 g HCl requires.

1000 mL 440.3 g pure HCl

X 3.65 g HCl X=8.3 mL

Therefore if you take 8.3 mL acid and dilute it to 1000 mL it will be 1 L, 0.1 N HCl. Donot forget, never add acid to

water, so put some water to volumetrik flask (balon joje), then add 8.3 mL of HCl. And mix it well, then complete it to

1000 mL till the line.

Preparation of 2.5 L 0.1N NaOH solution

1 L 1N NaOH solution 40 g NaOH required

2.5 L 0.1 N 10 g NaOH requires.

10 g of NaOH is weighted in watch glasses. Then it is moved to a beaker and dissolved in nearly

400 mL of water. Transfer it to the volumetric flask, fill it until 1L. Then transfer it to 2.5 L of

bottle. Add more 1.5 L water to this bottle and mix well. Do not forget to put label.