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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2018-09-01 11:38:57 | 106 | Physical Chemistry 251 C
Half life time
Deduce the equation which is used to determine the value of half live time t1/2 for the second order reaction. Read more

2018-08-31 21:35:39 | 0 | Kintic of the reactions 628 C
Effect of pH on enzymes
FACTORS AFFECTING ENZYME ACTIVITY Knowledge of basic enzyme kinetic theory is important in enzyme analysis in order both to understand the basic enzymatic mechanism and to select a method for enzyme analysis. The conditions selected to measure the activity of an enzyme would not be the same as those selected to measure the concentration of its substrate. Several factors affect ... Read more

قارن
قارن بين تفاعلات الرتبة الأولى و تفاعلات الرتبة الثانية. Read more

2018-08-30 20:00:35 | 7 | Transition Elements 311 C
General Properties
THE ELEMENTS OF THE FIRST TRANSITION SERIES ARE THOSE FOR WHICH THE 3D ELECTRON SHELL CONTAINS BETWEEN ONE AND NINE ELECTRONS. COPPER IS INCLUDED BECAUSE, ALTHOUGH ITS OUTER ELECTRONIC CONFIGURATION IS 3D10 4S1, IT HAS THE 3D9 CONFIGURATION IN ITS COMMONLY OCCURRING +2 OXIDATION STATE. ZINC IS NOT NORMALLY CONSIDERED A TRANSITION ELEMENT SINCE IN BOTH THE ELEMENT AND ITS ... Read more

2018-08-30 19:23:02 | 3 | Kinetic Theory 321 C
Gas Pressure
WHAT IS 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. When you blow air into a balloon, the balloon expands because the pressure of air molecules is greater on the inside of the balloon than ... Read more

2018-08-30 17:12:59 | 0 | Chemical Kinetics 222 C
chain reaction
Disuss the different steps in the chain reaction. Read more

2018-08-30 17:11:10 | 0 | Spectroscopic Methods of Analysis 531 C
Atomic Absorption
GRAPHITE FURNACE ATOMIC ABSORPTION spectroscopy (GFAAS) is a type of spectrometry that uses a graphite-coated furnace to vaporize the sample. Briefly, the technique is based on the fact that free atoms will absorb light at frequencies or wavelengths characteristic of the element of interest (hence the name atomic absorption spectrometry). Within certain limits, the amount of light absorbed can be ... Read more

2018-08-30 17:07:26 | 25 | Chemical kinetics 321 C
Inhibition of enzymes
COMPETITIVE INHIBITION is interruption of a chemical pathway owing to one chemical substance inhibiting the effect of another by competing with it for binding or bonding. In competitive inhibition of enzyme catalysis, binding of an inhibitor prevents binding of the target molecule of the enzyme, also known as the substrate. This is accomplished by blocking the binding site of the ... Read more

2018-08-29 20:30:14 | 95 | Transition Elements 311 C
Hg Properties
Mercury occurs in deposits throughout the world mostly as cinnabar (mercuric sulfide). The red pigment vermilion is obtained by grinding natural cinnabar or synthetic mercuric sulfide. Mercury is used in thermometers, barometers, manometers, sphygmomanometers, float valves, mercury switches, mercury relays, fluorescent lamps and other devices, though concerns about the element's toxicity have led to mercury thermometers and sphygmomanometers being largely ... Read more