Chemistry and Biochemistry Academy

  Hartmann dispersion formula is a semi-empirical formula. It is also referred to as Cornu Hartmann formula. It relates refractive index (n) with the wavelength (λ). It is given by:  n (λ)= X + Y/( λ-Z)............................................................Equation 1  X, Y, and Z are empirical constants while n (λ) is the refractive index of a material of light of wavelength λ. The constants derived as follows: Z= [(n 1 -n 2 )/ (n 2 -n 3 ) λ 1 (λ 2 - λ 3 ) - λ 3 - λ 3 (λ 1 - λ 2 )]/ [(n1-n2)/ (n2-n3) (λ2- λ 3 )-(λ1- λ 2 )]-....................................................................................Equation 2  Y= (n 1 -n 2 )/ [1/ (λ1-Z)-(1/ (λ2-Z)…………………………Equation 3  X=n 1 -B/ (λ1-Z)…………………………………………...Equation 4  Hartmann dispersion formula is applied in the measurements of spectra wavelengths taken on a prism instruments.  Constant Z is the spectrometer optical function. In the laboratory, it usually measured by lab technicians fo

For a better understanding of how to calculate pH of a buffer solution, you have to know a buffer solution. What is a buffer solution? It is a solution that resists vicissitudes in solution pH when small amounts of either acid solution or basic solution are added to that solution (a buffer solution). Therefore, a buffer solution obeys Le Chatelier’s Principle. Le Chatelier’s Principle states that when a system at equilibrium is subjected to any change, the system readjusts itself to resist the effect (s) of the change. This results in the establishment of a new equilibrium. The change can either be pressure or temperature or concentration.  A buffer solution can be an acid or a base. An acidic buffer solution resists the removal of hydrogen ions. On the other hand, an alkaline buffer resists the removal of hydroxide ions. Up to this point, you can now calculate the pH of a buffer solution. However, you have to identify whether the buffer solution is an alkaline

Cuprous bromide is also known as copper (I) bromide is a chemical compound. CuBr is the chemical formula of cuprous bromide. Cuprous bromide (solid) is diamagnetic. It espouses a polymeric chemical structure, which is the same that of zinc sulfide.  Chemical structure of cuprous bromide  Cuprous bromide coordinates to form Cu4Br4 Cubane Tetramer. Cuprous bromide is a face-centered cubic consisting of anions and cations occupying ½ of the holes (tetrahedral holes).Every ion is a 4-coordinate and has a local tetrahedral geometry. Figure 1: Red balls represent Cu - while the blue balls denote Br - .Copper ions occupy only one-half of the holes (tetrahedral holes). Figure 2: Yellow balls represent Br - ions while slate blue balls represent copper ions. As in Figure 1, copper ions occupy one-half of the tetrahedral holes. Characteristics of cuprous bromide ·          Cuprous bromide is colorless. However, its samples are always colored as a r