New Concepts/Shortcuts 21 Flashcards
what are activators in enzyme reactions?
what do they do and give on eg of them?
Activators are generally metal ions such as Na+ , Mn2+ , Co2+ , Cu2+ etc. These metal ions, when weakly bonded to enzyme molecules, increase their catalytic activity. Amylase in presence of sodium chloride i.e., Na+ ions are catalytically very active
What’s used the in contact proces and whats the contact process?
whats the colloid particle size range
Colloidal particles are larger than simple molecules but small enough to remain suspended. Their range of diameters is between 1 and 1000 nm (10–9 to 10–6 m).
why does the colloidal particle have an enormous surface area per unit mass?
Colloidal particles have an enormous surface area per unit mass as
a result of their small size
whats kraft temperature and critical micelle concentration?
The formation of micelles takes place only above a particular temperature called Kraft temperature (Tk) and above a particular concentration called critical micelle concentration (CMC)
what happens on dilution of micelle solution
On dilution, these colloids revert back to individual ions
whats associated colloids?
There are some substances which at low concentrations behave as normal strong electrolytes, but at higher concentrations exhibit colloidal behaviour due to the formation of aggregates. The aggregated particles thus formed are called micelles. These are also known as associated colloids
why does the Tyndall effect occur?
The Tyndall effect is due to the fact that colloidal particles scatter light in all directions in space. This scattering of light illuminates the path of the beam in the colloidal dispersion
explain the cleansing action of soaps
the polar groups can interact with water, the oil droplet surrounded by stearate ions is now pulled in water and removed from the dirty surface. Thus soap helps in emulsification and washing away oils and fats. The negatively charged sheath around the globules prevents them from coming together and forming aggregates.
how are colloidal dispersions made from chemical reactions?
what happens in bredig’s arc method?
this process involves dispersion as well as condensation. Colloidal sols of metals such as gold, silver, platinum, etc., can be prepared by this method. In this method, electric arc is struck between electrodes of the metal immersed in the dispersion medium.The intense heat produced vapourises the metal, which then condenses to form particles of colloidal size.
whats peptization?!
Peptization may be defined as the process of converting a precipitate into colloidal sol by
shaking it with dispersion medium in the presence of a small amount of electrolyte. The electrolyte used for this purpose is called peptizing agent
What’s the concept of dialysis?!
Since particles (ions or smaller molecules) in a true solution can pass through an animal membrane (bladder) or parchment paper or cellophane sheet but not the colloidal particles, the membrane can be used for dialysis. The apparatus used for this purpose is called a dialyzer. A bag of suitable membranes containing the colloidal solution is suspended in a vessel through which fresh water is continuously flowing (Fig. 5.9). The molecules and ions diffuse through the membrane into the outer water and the pure colloidal solution is left behind.
whats Ultrafiltration?
Ultrafiltration is the process of separating the colloidal particles from the solvent and soluble solutes present in the colloidal solution by specially prepared filters, which are permeable to all substances except the colloidal particles
Whats a collodion solution?
the pores of filter paper can be reduced in size by impregnating it with collodion solution to stop the flow of colloidal particles. The usual collodion is a 4% solution of nitrocellulose in a
mixture of alcohol and ether
how can we make an ultra filter paper!?
An ultra-filter paper may be prepared by soaking the filter paper in a collodion solution, hardening by formaldehyde and then finally drying it.
why does ultra microscope not provide any information about the size and shape of colloidal particles?
Ultramicroscope does not render the actual colloidal particles visible but only observe the light scattered by them. Thus, ultramicroscope does not provide any information about the size and shape of colloidal particles.
how can a mixture of milk and water appear blue?
a mixture of milk and water appears blue when viewed by the reflected light and red when viewed by the transmitted light
how and why does the color of gold sol change?
The finest gold sol is red in color; as the size of particles increases, it appears purple, then blue, and finally golden.
brownian motion is dependent on?
This motion is independent of the nature of the colloid but depends on the size of the particles and viscosity of the solution. Smaller the size and lesser the viscosity, faster is the motion.
What’s the explanation of brownian motion?
The Brownian movement has been explained to be due to the unbalanced bombardment of the particles by the molecules of the dispersion medium. The Brownian movement has a stirring effect which does not permit the particles to settle and thus, is responsible for the stability of sols.
what provides stabilty to collloidal solution?
conformations of butane
stability order of the butane conformations
