lobna.nassr

Lobna Abdel-Mohsen Ebaid Nassr

Professor - Head Of Chemistry Department- Director of Quality Management Unit - Faculty of Science - Sohag University

Faculty of science

Address: Chemistry Department - Faculty of Science - Sohag University

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Density of transition elements

2018-11-30 21:38:13 Transition Elements 311 C
The densities of transition elements The densities of transition elements are high, most of them have d > 5 gm/cm3 Density initially increases across each series and then decreases. The densities of the transition ... Read more

Melting and boiling points of transition elements

2018-11-30 21:36:59 Transition Elements 311 C
Melting and boiling points of transition elements Melting points and boiling points of transition elements are very high. Most of melting points are higher than 1000 C. 3 elements melt above 3000 C (melting ... Read more

Size of transition elements

2018-11-30 21:36:59 Transition Elements 311 C
Size of transition elements The radii decrease with increasing atomic number and then increase again toward the end of each transition series. Ni has the smallest radii among the transition elements On descending from ... Read more

Electron configuration

2018-11-30 21:21:36 Transition Elements 311 C
AUFBAU PRINCIPLE AND MADELUNG RULE The Aufbau principle (from the German _Aufbau_, "building up, construction") was an important part of Bohr's original concept of electron configuration. It may be stated as: The approximate order ... Read more

Equilibrium

2018-11-29 23:10:31 Physical Chemistry 251 C
EQUILIBRIUM State in which NO SPONTANEOUS CHANGES are observed with respect to TIME. WE ACTUALLY NEVER TOTALLY ACHIEVE EQUILIBRIUM, WE ONLY APPROXIMATE IT. IT TAKES INFINITE TIME TO ACHIEVE FINAL EQUILIBRIUM * MECHANICALEQUILIBRIUM: characterized ... Read more

Phase and Phase

2018-11-29 22:53:53 Physical Chemistry 251 C
PHASE: a quantity of matter that is homogeneous throughout. Examples of single phase: ICE WATER PHASEBOUNDARIES: interfaces between different phases. A glass of ice water is a two-phase mixture with the phase boundaries at ... Read more

van der Waals equation

2018-11-29 22:41:29 Kinetic Theory 321 C
The VAN DER WAALS EQUATION (or VAN DER WAALS EQUATION OF STATE; named after Johannes Diderik van der Waals) is based on plausible reasons that real gases do not follow the ideal gas law. ... Read more

Gas Pressure

2018-11-29 22:07:21 Kinetic Theory 321 C
GAS PRESSURE Pressure is a force exerted by the substance per unit area on another substance. The pressure of a gas is the force that the gas exerts on the walls of its container. ... Read more

Distribution of Molecular Speeds

2018-11-29 21:55:31 Kinetic Theory 321 C
THE MAXWELL-BOLTZMANN DISTRIBUTION The motion of molecules in a gas is random in magnitude and direction for individual molecules, but a gas of many molecules has a predictable distribution of molecular speeds. This predictable ... Read more

Solvent Cage Effect

2018-11-29 21:17:12 Chemical kinetics 321 C
THE SOLVENT CAGE EFFECT In the solution, the reactant molecules will remain close to each other for some times, being surrounded by a CAGE OF SOLVENT MOLECULES. This cage effect becomes more significant when ... Read more