Lecture 1 contents The nature of analytical chemistry. Qualitative and quantitative analysis. Sensitivity of analysis.  Solution.   Electrolytes. Solubility rules.

Quantitative Analysis Qualitative Analysis Analytical Chemistry Quantitative Analysis Qualitative Analysis Gravimetric Analysis Instrumental Analysis Volumetric Analysis

It is a Measurements science consisting of a set of powerful ideas and methods that are useful in all field of science and medicine.

Qualitative Analysis (identification) Provides information about the elements and compounds in a sample. “Identifying what is in unknown” Quantitative Analysis provides information about the amount of each substance in a sample . “Identifying how much is present”

Qualitative analysis is what. Quantitative analysis is how much. ©Gary Christian, Analytical Chemistry, 6th Ed. (Wiley)

Analyets Substances being measured Species Any chemical of interest in the analysis

Sensitivity of analysis Trace analysis = 1-1000 ppm or 0.0001-0.1 wt.% Ultrtrace analysis = < 1ppm or 0.0001 wt.% Macro- = >1mg Micro- = < 1 mg

The Role of Analytical Chemistry Analytical chemistry plays a vital role in the development of science. Plays a vital role in many research areas in chemistry, biochemistry, biology, geology, physics and the other sciences. All branches of chemistry draw on the ideas and techniques of analytical chemistry. All branches of chemistry draw on the ideas and techniques of analytical chemistry

Where is Analytical Chemistry used? 1- Clinical laboratories. 2- Forensic laboratories. 3-Environmental laboratories. 4- Manufacturing /industry 5- Research. 6- Others.

Analytical chemistry and other branches of sciences

Steps in chemical analysis

Steps in chemical analysis 1- Formulating the question. 2- Selecting the analytical procedure.

Steps in chemical analysis 3- Sampling Sampling: selecting representative material to analyze

Steps in chemical analysis 3- Sample preparation

Steps in chemical analysis 4- Interpretation and reporting 5- Drawing conclusions

Sample preparation 1- sample storage(e.g. temperature, moisture) 2- Grinding ,extracting analyte ,etc

Sample preparation 3- Dissolving sample, dispersing analyte) 4- Concentrating analyte.

Sample preparation 5- Eliminate interfering/ “mask” species (drying , ingnition ,isolation).

Types of Analysis Gravimetric Methods: Measure the mass of the analyte or some compound chemically related to it. Volumetric Methods: Measure the volume of a solution containing sufficient reagent to react completely with the analyte .

Quantitative Analytical Methods Spectroscopic Methods: measurement based on interaction between electromagnetic radiation and analyte . Mass spectrometry Measure of mass to charge ratio (m/z) of analyte. Electroanalytical Methods: measure of electrical properties such as voltage, current, resistance and quantity of electrical charge. Others : Radioactive decay, heat of reaction, optical activity, refractive index, rate of reaction

Measurements SI Units (International System of Units)

Measurements Prefixes used with SI Units

Mass /amount of substance Mass kilogram (kg) gram (g) Amount of substances moles (mol) 1 mole = 6.022×1023 particles (e.g. atoms, molecules, ions) . Atomic mass = number of grams containing  Avogadro's number (6.022×1023 ) of atoms Molecular mass = number of grams containing Avogadro's number (6.022×1023 ) of molecules; sum of atomic masses of elements in a molecule

Solution solution Solution : A homogenous mixture of two or more substances, the solute and the solvent. A solute is what dissolves or disappears, like salt or sugar. A solvent is what does the dissolving. solute solvent

Examples Example: Salt water Example – 70% ethanol solution. What is the solute?______ What is the solvent?___________ Example – 70% ethanol solution. Solute _______________ Solvent________________ Why? Salt water Water ethanol If 70% is ethanol, then it must be the solvent. The remaining 30% is water, the solute.

Solute dissolve to form Solution -Solutions can be electrolytes or non- electrolytes . Solute dissolve to form Ions electrolytes Molecules Non-electrolytes

Some non-electrolytes can also dissolve in water Solution Some non-electrolytes can also dissolve in water

Solution e.g. NaCl salt

Electrolyte Electrolytes: A substance that dissociates into ions in aqueous solution and conduct electricity.

Like dissolves like

Making solutions