THEORY Evaporation is the removal of solvent as vapour from a solution. There are four factors that affect evaporation, the area of exposed water surface the larger the area, the greater the loss; the temperature of the water and air above it a higher temperature increases loss; the movement of air above the water surface a greater movement carries off more vapour; and the relative humidity dry air absorbs moisture more readily than moist air. According to the kinetic theory of evaporation, molecules of water are in a constant state of random motion, colliding with one another, and rebounding. In the liquid state, these molecules are held in balance bycohesive force; however, some molecules possess sufficient kinetic energy to overcome this cohesive force and break free from the water surface, thus forming gaseous molecules. The fundamental law of evaporation is credited to Dalton (87).
These values are in Appendix A. Bubbles from cavitation occur when suction pressure was raised higher than the vapor pressure. Cavitation causes harm to a system as it “reduces the pump capacity and causes severe erosion” . Cavitation can be prevented by the vapor pressure being exceeded by the inlet pump pressure, or the NPSH . A cavitation experiment was performed to determine the NPSH at a pump speed of 3000-rpm, using the pressure drop and flow rate.
This column – of a large surface area with glass or ceramic – provides ample contact between the vapor and liquid phases. A temperature gradient is formed because the head of the system is now further from the flask. Factors that affect the temperature gradient include the rate of heating and vapor removal from the system’s stillhead. Upon heating, the vapor of compound A rises, reaching a distance at which it no longer has enough energy to maintain its gaseous form; at this point, the molecules re-enter the liquid state. This process of rising up, condensation, and revaporization eventually results in vapor comprising 100% of substance A.
It will cause more oxygen to be produced thus result in the increase of the final volume of foam in each measuring cylinder than actual value. The rate of reaction of enzyme will then higher than expected. One possible solution for this error is changing the ruler into another measurement instrument such
As the stearyl group is at 1-postion in GMS, lipase favors its hydrolysis . Pancreatic lipase possesses higher affinity towards MCT compared to LCT. Hence, NLCs containing MCT will be hydrolyzed more extensively during in vitro lipolysis [83, 85]. The study conducted by Dahan and Hoffman showed that the hydrolysis of MCT of the lipid based formulation has resulted in a high concentration of lipophilic drug solubilized in the aqueous phase when compared to LCT and short chain triglyceride (SCT). Also, the formulations containing MCT underwent a complete lipolysis; hence, no undigested oil remained after the digestion of 30 min
THE RATE THEORY OF CHROMATOGRAPHY This theory describes the actual process going on inside the chromatographic column with respect to the time taken for the solute to equilibrate between the stationary and mobile phase. The kinetic effect depends upon how much time the mobile phase spends in contact with the stationary phase. The rate of elution affects the band shape of a chromatographic peak. It is also affected by the different paths available to solute molecules as they travel between particles of stationary phase. The reason for band broadening was well explained by Van Deemter equation for plate height HETP = A + B/u + Cu where u is the average velocity of the mobile phase.
On the other hand, Supersaturation means that the concentration of the ions that make up the stone forming salt exceed their solubility in the urine, causing the ions to interact and precipitate as a solid phase crystal. The formation of renal stones is a consequence of increased urinary super saturation with subsequent formation of crystalline particles (Carvahlo and Nakagawa, 1999; Daudona and Jungers, 2004; Verdesca et al., 2011; Ouyang et al., 2012). Among the most common expression
The sooner hemolysis occurs , the greater the osmotic fragility of the cells ( Parpart etal. , 1947 ). The tests are based on the measure of red blood cell lysis as a function of osmotic stress. When erythrocytes are placed in hypotonic solutions, they begin to take on water osmotically. This results in swelling of the cell until the critical volume is reached, afterward the membrane at first leaks and then bursts releasing hemoglobin (Faulkner and king 1970 ).
The mixture is dissolved in a fluid called the mobile phase, which carries it through a structure holding another material called the stationary phase. The various constituents of the mixture travel at different speeds, causing them to separate. The separation is based on differential partitioning between the mobile and stationary phases. Principle of Chromatography: The mixture is dissolved in a fluid called the mobile phase, which carries it through a structure holding another material called the stationary phase. The various constituents of the mixture travel at different speeds, causing them to separate.
Tare the scale. 4. Measure out 1,575g of oxalic acid crystals into the glass beaker. 5. Determine the mass of the beaker and NaOH together.