ChemistryChemistryIntroductionIntroduction

Dr. Mohamed Abd-Elhakeem

College of Biotechnology

General Chemistry

Lecture 1

• What is the chemistry?• What happened if the atomic structure collapse?• Why water don’t burn?• How we can calculate the calories of food?• What is the mechanism of air condition?• What are the information that can be obtained from

the periodic table?• What is the mean of color and how it is formed?• How can we determine the constituents in your juice?• How the atoms bind to each other to form compounds?• Why water able to dissolve salt and not able to solve

oil?• Do you hear about bio battery?• Do you know about the revolution of nanotechnology?

ChemistryChemistry• Chemistry = the study of matter and the

transformation it undergoes EVERYTHING is a CHEMICAL

o Table salt = sodium chloride, NaClo Table sugar = sucrose, C12H22O11

o Clothes: Wool? Cotton? Polyester?o Body: lipids, Proteins, Carbohydrates,

DNA/RNAo You name it– it’s a chemical!

Chemistry as the Chemistry as the “Central Science“Central Science””

Macroscopic, Microscopic & Particulate Macroscopic, Microscopic & Particulate

MatterMatter

• Matter: “ Anything that has mass and takes up space (occupies volume)“

Classification of Classification of MatterMatter

4 Physical States: solid, liquid, gas, plasma

Solid:Fixed shape and fixed volume; Atoms tightly packed together

Classification of Classification of MatterMatter

Liquid:No fixed shape but maintains a fixed volume Atoms loosely packed together, slide around

each other

Classification of Classification of MatterMatter

Gas:No fixed shape or volumeAtoms not really associated with

neighbors at all

Classification of Classification of MatterMatter

Plasma:mix of subatomic particles with not organization (sun)

Microscopic view of a gas.

Microscopic view of a liquid.

Microscopic view of a solid.

Properties of MatterProperties of MatterPhysical Properties =

characteristics of a material

Color MassTemperatureOdorDensityHardnessSolubilityConductivity (heat or

electrical)Freezing/boiling point

Chemical Properties = describe how a material reacts with another type of matter

Ability to burnAbility to rust / corrodeAbility to make a

solution acidic or basicLack of ability to react

with something

Changes in Matter - Changes in Matter - Physical & Physical &

ChemicalChemical

• Physical Change: “ A change that alters the physical form of matter without changing its chemical identity “

• Chemical Change: “ A change which changes the chemical identity of the substance and creates one or more new substances “

Changes in Matter - Changes in Matter - Physical ChangePhysical Change

A Melting Ice Sickle

Solid Water

Liquid Water

•Example of a Physical Change:

Changes in Matter - Changes in Matter - Chemical ChangeChemical Change

•Example of a Chemical Change: The Electrolysis of Water (H2O)

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Hydrogen Gas

Oxygen Gas

Negative Electrode Positive Electrode

ParticulateViewpoint

The Chemical Identity of Water ( H2O ) is changed

into the elements Hydrogen ( H2 ) and Oxygen ( O2 )

2H2O 2H2 + O2

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Classification of Matter

Matter - Anything that occupies space and has

mass (solid, liquid or gas)

Heterogeneous Mixture: Non-uniform composition

Homogeneous Matter: Uniform composition

Pure Substances: Fixed composition; cannot be

further purified

Physically Separable Into

Solution: Homogeneous

mixturePhysically Separable Into

Compounds: Elements united in

fixed ratios

Elements: Cannot be subdivided by

chemical or physical changes

Chemically decomposable Into

Combine Chemically to

Elements - The Most Simple Kind of Matter

Pure Substance: Matter that cannot be separated into two or more types of matter by physical means is called pure matter. Pure matter consists of two types, elements and compounds.

Element: Elements are substances that cannot be separated into two or more types of matter by physical or chemical methods.

Chemical Compounds - Atoms in Combination

Chemical Compounds: “Compounds are composed of two or more elements chemically combined in definite ratio”

OrAny pure substance that can be decomposed by a chemical change into two or more pure substances

Examples: H2O Water

NaCl Sodium Chloride

C2H6O Ethanol

C6H12O6 Sugar

MixturesMixtures

• Mixture is the type of substance that can be physically separated into more than one component. It may be homogeneous or heterogeneous.

•  o A homogeneous mixture: (called also A solution), is a

mixture that has the same composition and properties throughout.

o A heterogeneous mixture: varies in composition and/or properties from one part of the mixture to another as in a glass of ice water

Sugar dissolved in water

Gold blended with silver (18 karat gold)

The air we breathe - a mixture of oxygen and nitrogen

Solutions: “Homogeneous mixtures, either liquid, solid or gaseous”

Homogeneous mixture

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Table salt is stirred into water (left), forming a homogeneous mixture called a solution (right)

Heterogeneous Sample:

•A mixture of cooking oil and water (two phases develop

•Concrete (sand, rock, cement, etc)

•A mixture of sand, sawdust, iron fillings and water

Sand and water do not mix to form a uniform mixture

Mixtures and Pure Substances (cont)

continue…..

Classification of Classification of MatterMatter

Chemistry branchesChemistry branches• Chemistry is typically divided into several major sub-

disciplines. There are also several main cross-disciplinary and more specialized fields of chemistry.

• Analytical chemistry is the analysis of material samples to gain an understanding of their chemical composition and structure.

• Biochemistry is the study of the chemicals, chemical reactions and chemical interactions that take place in living organisms. Biochemistry and organic chemistry are closely related, as in medicinal chemistry or neurochemistry. Biochemistry is also associated with molecular biology and genetics.

• Inorganic chemistry is the study of the properties and reactions of inorganic compounds.

• Nuclear chemistry is the study of how subatomic particles come together and make nuclei.

• Organic chemistry is the study of the structure, properties, composition, mechanisms, reactions and synthesis of organic compounds. An organic compound is defined as any compound based on a carbon skeleton.

• Physical chemistry is the study of the physical and fundamental basis of chemical systems and processes. In particular, the energetics and dynamics of such systems and processes are of interest to physical chemists.

• Quantum chemistry providing a mathematical description of the dual particle-like and wave-like behavior and interaction of matter and energy

Chemical symbolChemical symbol• chemical element is identified by an internationally

used symbol consisting of one or two letters.

• The first letter of an element’s symbol is always capitalized. If the symbol has a second letter, it is a lowercase (small) letter.

• The symbol is an abbreviation of the element’s name, but some symbols represent names in languages other than English.

SymbolsSymbols• All elements have

their own unique symbol.

• It can consist of a single capital letter, or a capital letter and one or two lower case letters.

C Carbon

CuCopper

• What is the difference between

CO and Co

• Chemical formula shows the kind and proportion of atoms of each element that occurs in a particular compound

Symbol Name Symbol NameSbAuFePbHgKAgNaSnWPZnHeNeAr

Antimony Gold Iron Lead Mercury Potassium Silver Sodium Tin TungstenPhosphorus ZinkHeliumNeonArgon

HOCCaMgMnCuClBrIFS

HydrogenOxygen CarbonCalcium MagesiumManganeseCupper Chlorine Bromine IodineFlourine Sulpher