REACTION KINETICS
Reaction rate studies conducted at conditions similar to industrial conditions provides valuable engineering data for full scale reactor design.
In a typical oxidative pressure leaching process, the mass transfer that is required to sustain a heterogeneous reaction takes place at the boundary between two phases, which is called the reaction interface. Obviously one of the phases is solid, so it is the reaction at the solid surface.The total reaction rate of heterogeneous processes is controlled by the rate of the slowest step.
Figure 5 1 below shows a schematic diagram of the sequential process (1 to 6) for the leaching reaction of a solid particle
Dispersion of oxygen into the pulp Fluid film mass transfer Diffusion
…show more content…
Unreacted shrinking core model
The unreacted shrinking core model is applied when the reactant is converted to another solid material leaving behind a product layer around the unreacted particle core.
Figure 5.3: Schematic diagram of shrinking core model
The mathematical description of the shrinking core model under product diffusion control is based on the following assumptions The particle is considered to maintain its shape and size during the entire leaching process The low reaction and product concentrations in solution means the net flux due to diffusion is considered negligible The surface reaction is assumed to be first order and irreversible with respect to the reacting reagent. The reaction reagent is in excess and its concentration may be considered constant during the entire leaching process. The system may be considered to be in quasi steady state.
Considering J to be the flux of B in Reaction 5.2 through a product layer in time t, then from Fick’s law: "J = -4π" "l" ^"2" "D" _"s" "dC" /"dl"
The reaction was repeated 3 times and average rate noted. From these rates a graph was plotted which describes the relationship of the pressure produced and number of drops added. The reaction rates were measured by Kpa/min and were written to 4 figures for precise results. Time was measured by stop watch. Table 4 shows a summary of all the groups which participated in the lab session.
Tyler White CHEM151LL 32658 04/01/2018 Different Types Chemical Reaction Types and Equations Purpose: The purpose of this lab experiment is to examine different types of chemical reactions such as Decomposition reaction, Synthesis reactions, Combustion reactions, and different Chemical equations. The experiments were conducted online using Late Nite Labs. Materials: Because the experiments were conducted online there wasn’t any physical use of materials, only digital ones, for these labs to be performed. Only the registration for the website was needed to perform these online labs, as well as a desktop computer.
1. Introduction The objective of the experiments was to determine the identity of an unknown compound in order to properly dispose it. The process of disposal is very important when dealing with chemicals. Some chemicals are very
To better understand this law, Cu(s) was transformed with different reactions only to return back to Cu s). The initial and final mass of Cu(s) was recorded to give the percent recovery of copper product at
This implies that the combustion product contains more elements and should have more mass than the original. Ferric oxide is not attracted to a magnet and is not attracted to
The average reaction time for Run 2 without catalysis was 73.68s and with catalyst was 12.13s, which have a big difference, the average reaction time for Run 2 with he catalyst was much faster than the one without the catalyst. Based on the result of average reaction time, the catalyst helps reaction to increase the rate of the reaction. Collision theory states that the particles in the reaction should collide with a certain minimum energy, which is called the activation energy. If
Abstract In this experiment, the reaction kinetics of the hydrolysis of t-butyl chloride, (CH3)3CCl, was studied. The experiment was to determine the rate constant of the reaction, as well as the effects of solvent composition on the rate of reaction. A 50/50 V/V isopropanol/water solvent mixture was prepared and 1cm3 of (CH3)3CCl was added. At specific instances, aliquots of the reaction mixture were withdrawn and quenched with acetone.
With many factors affecting chemical reactions, there is a significant relationship between these factors and the rate that they occur. As seen through many studies and experiments, surface area of solid reactants has a great impact on this rate of reaction. In conclusion, the scientist has learned important relationships and factors involved in the rate of which chemical reactions
With the data collected from this chemical reaction percentage yield of the precipitate can be calculated to determine the effects of impurities in the reactants on percentage yield. PRE-LAB QUESTIONS 1. What is the balanced chemical equation for the reaction in this investigation? 2. Which reactant is considered impure in this investigation?
Table 1 Results DDA Concentration Initial Mass(g) Time Interval Recovered Mass Cumulative Mass (g) Cumulative Recovery (%) Ln[(Rinf -R)/ Rinf] R=Rinf(1-e-kt) (M) (g) 10^(-5) 160 0 0
Another variable of the experiment that was controlled was the time in which the agar cubes spent in the sulphuric acid. The time allowed calculation of the rate of diffusion. The size of the agar cubes was controlled by using a grid and scalpel to, as accurately as possible, cut the agar cubes into the appropriate sizes. The shape of the agar cubes was also controlled. In future, this could be experimented with to investigate how different shaped agar blocks affect surface area to volume ratio and hence the rate of
Considering that the reaction was done a micro scale the amount of waste is limited (Prevention #1). Bleach was used in this reaction instead of a chromium compound. Bleach is less hazardous in comparison, therefore less hazardous chemical syntheses (#3) was followed. Consider that all waste can be safely disposed with merely water, and that the chemicals used are at most irritates, then potential for harmful chemical accidents is limited (Inherently Safer Chemistry for Accident Prevention #12). 2.
Practical Report- Diffusion in Agar Cubes Sabrina Turtur- Stage 1 Biology Introduction Diffusion is the movement of particles (atoms, ions or molecules) from an area in which they are in higher concentration to areas of lower concentration. It continues until the concentration of substances is the same throughout. The act of diffusion occurs in respiration, photosynthesis and osmosis. Without it, cells would not receive the nutrients they need to resume stability.
Ideally, every mole of each reagent would be used up, and theoretical yield, we are assuming that every last mole of the reactants would
(Molarity)(Volume)(Molar mass) The pellets were dissolved thoroughly then was used in filling up the 100 mL volumetric flask. The solution was mixed well