Chemistry Notes for B.Sc. and M.Sc.

Hotspots of biodiversity   “Hotspots of biodiversity " are the areas on Earth which possess both high biodiversity as well as high species endemism . Besides the biodiversity richness, these areas are also severely affected by human activities (deforestation, agriculture, urbanization, or environmental hazards at some point of time. These points prioritize them for taking conservative measures . High Species Endemism : High Species Endemism means these areas provide shelter to many unique, endemic species that are found nowhere else in the world. Endemic Species : The species of living organisms which are found in a particular geographic region and nowhere else in the world. The concept of “ Hotspots of biodiversity ” was popularized by the ecologist Norman Myers in 1988 . Qualifying Criteria for a Biodiversity Hotspot : High Endemism: The region must contain over 1500 endemic species of plants and also high endemic species of animals. Threatened status: ...

Hooke's Law is an equation which help s in interpreting the molecular vibrations  by assuming bonds as spring having masses (atoms) at two ends. When a molecule is exposed to infrared light, the  bonds between atoms can absorb specific frequencies of that light, causing the bonds to stretch ,  compress  or bend , just  like a spring.  This characteristic absorption of light corresponding to certain  specific vibrational frequencies helps in identifying the functional groups in that  molecule and thus adding to  the characterization of molecular structures.  The mathematical expression of Hooke’s law is given as follows: ν  = 1/2π√k/µ ῡ = 1/2πc√k/µ where: ·  ν  = the frequency of vibration ·  ῡ = Wave number (reciprocal of wavelength) ·  k  = the force constant ·  c = Velocity of light ·  Π = Constant ·  μ = reduced mass The reduced mass of the two atoms involved in the bond  is  calc...

The Beer-Lambert Law   states that   the absorbance of light by a medium is direct ly proportional to   its concentration   as well as path length (the distance travelled by the light) . The law can be expressed mathematically as: A   = ϵcl   = log( I 0 /I) Where:   A   = A bsorbance (measure of the amount of light absorbed).   ·  I 0 = Intensity of incident Light ·  I = Intensity of transmitted Light ·  ϵ   =   M olar absorptivity   Constant   ·  c =   the concentration of the solute ·  l =   the path length of the sample (the distance light travels through the solution ) Units: ·  A   = unitless ·  ϵ   =   cm 2 /mol ·  c =   mol/L ·  l =  cm M olar absorptivity   Constant ( ϵ )   --- A   constant that indicates how strongly a substance absorbs light at a particular wavelength.   It is characteristic of a substance and is i...

  Isotopes: Isotopes are the atoms of an element having same atomic number but different mass number. They also have the same number of protons . Example  1 : ·  Hydrogen   has three   isotopes : o  Protium ( 1 H 1 ) : Atomic Number = Number of protons = 1, Mass number = 1 o  Deuterium ( 1 H 2 ) : Atomic Number = Number of protons = 1, Mass number = 2 o  Tritium ( ( 1 H 3 ) :   Atomic Number = Number of protons = 1, Mass number = 3 Ex ample  2 : ·  Carbon   has two   isotopes : o  Carbon-12 ( 6 C 12 ) : Atomic Number = Number of protons = 6, Mass number = 12 o  Carbon-14 ( 6 C 14 ) :   Atomic Number = Number of protons = 6, Mass number = 14 समस्थानिक : समस्थानिक   एक   तत्व   के   परमाणु   होते   हैं   जिनकी   परमाणु   संख्या   समान   होती   है   लेकिन   द्रव्यमान   संख्या   भिन्न   होती   है।   उनके ...