This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Int roduction: Chemical kinetics is the study of the rate of a chemical reaction, by observing the factors that affect these rates (such as concentration, temperature etc). To describe the rate of a reaction, we can qualitatively observe changes in the state and physical appearance of the reactants (colour, for example), or use general descriptors such as “fast” or “slow.” However, to quantitatively measure the rate, we can use various methods, including the application of several formulas. The general formula for the rate of a reaction is Rate = k [A] n [B] m The product of the concentrations of the reactants, each raised to a power, describes the rate. A constant, k, is applied since the reaction is a proportionality. The powers n and m, describe the order of the reaction. An order of 1 will create a linear graph, while a higher order will create an exponential graph. While other variables are being held constant, it is possible to determine change in concentration of each of the reactant, which is to say, the partial order with regard to each reactant. The partial order is determined experimentally. When the reaction is graphically analysed, it is said to be displaying pseudo first-order behaviour if the logarithm of the reaction graph reveals a linear plot. Spectrophotometry is the study of chemical characteristics using light. Light is projected though a substance, and determines how much light gets through. Part of it can be diffused or reflected by the substance. Most of it will be absorbed. (Lothian) 1 Tests can be performed to calculate the amount of light absorbed by the substance, both qualitatively (by noting the opacity of the substance) and quantitatively (using a spectrophotometer). In the lab, a spectrophotometer is used to determine the opacity of a 1 1 G.F. Lothian, M.A., F.Inst.P. Absorption Spectrophotometry , 2d ed., Hilger & Watts LTD, 3,7 (1958). P. W. Atkins, "Physical chemistry", in [email protected], http://www.accessscience.com.proxy.bib.uottawa.ca, DOI 10.1036/1097-8542.513600 chromium I I I nitrate and EDTA (ethylene(dinitrilo)tetraacetate) solution, as they react to form a chromium I I I-EDTA complex. Procedure: As described in the lab manual. Observations and Results: Table : Qualitative Observations Overall The temperature of the water bath was kept around 22°C. All of the solutions got progressively darker in colour as the experiment progressed. This change was noticeable by the end but was very gradual....
View Full Document
This note was uploaded on 01/17/2010 for the course CHM BIO1130 taught by Professor Houseman during the Fall '09 term at University of Ottawa.
- Fall '09