IBDP Chemistry IA: Equilibrium Reaction Lab Introduction: Reactions are based on collisions of particles, in which the particles must have sufficient energy. Some chemical reactions are reversible, and when the rate of the forward reaction equals the rate of the reverse reaction, the process has reached equilibrium. As it will appear to have stopped, as there is no overall change due to the rates being equal. Through this lab, we will be investigating one factor that will affect the equilibrium constant. The chemical reaction to determine the equilibrium constant is; 〖Fe〗^3 +_((aq))+SCN-_((aq))⇌ 〖FeSCN〗^2 +_((aq)) And to calculate the equilibrium constant; K_c K_c= ( [〖FeSCN〗^(2+)])/([〖Fe〗^(3+)] [〖SCN〗^-]) To obtain the value of K_c of this reaction, we need to know the concentrations of iron (III) and thiocyanate. When the two solutions are mixed together, wait for a period of time to ensure equilibrium. As equilibrium is reached, we can apply ‘ICE’ method to calculate the concentration of thiocyanatoiron (III), x. K_c= ( x)/(([〖Fe〗^(3+) ]-x) ([〖SCN〗^- ]-x)) Out of the three substances, SCN- is colourless, while 〖Fe〗^(3+) is dull yellow in 0.5M of〖 HNO〗_3. So the dominant colour for this equilibrium would be thiocyanatoiron (III) in brownish red which absorbs blue light. And so by using Beer-Lambert’s law, we will be able to calculate x: x=A/(ε×l) From the equation above, A is absorbance of the solution in equilibrium, ε is the molar absurdity of the molecule and l is the cuvette width; the length of which light goes through the cuvette. Extra information: Beer-Lambert Law states the absorbance of light at a certain wavelength is directly proportional to the concentration of a solution. Which basically means the darker t... ... middle of paper ... .../hwb/chemistry/tutorials/molspec/beers1.htm Calculations in Science. (n.d.). - Beer's law. Retrieved May 23, 2014, from http://calcscience.uwe.ac.uk/beers-law.aspx Downloads. (n.d.). Spectrophotometers Cuvettes. Retrieved May 23, 2014, from http://www.jenway.com/product.asp?dsl=302 Plastic Cuvettes (visible range). (n.d.). > Vernier Software & Technology. Retrieved May 23, 2014, from http://www.vernier.com/products/accessories/cuv/ Spectrophotometry. (n.d.). : Beer's Law. Retrieved May 23, 2014, from http://www.chm.davidson.edu/vce/spectrophotometry/beerslaw.html What Is a Colorimeter?. (n.d.). wiseGEEK. Retrieved May 23, 2014, from http://www.wisegeek.org/what-is-a-colorimeter.htm absorption spectra - the Beer-Lambert Law. (n.d.). absorption spectra - the Beer-Lambert Law. Retrieved May 23, 2014, from http://www.chemguide.co.uk/analysis/uvvisible/beerlambert.html
Absorbance was defined as: log I_o/I where I_o is incident light and I is the transmitted light. Fluorescence emission spectrum is different from fluorescence excitation spectrum because it records different wavelengths of chemical s...
The limiting reactant of a chemical reaction is the substance that places an upper bound on the amount of product that the reaction can produce. The limiting reactant places this upper bound because the reaction must stop once all of the limiting reactant is consumed.
Abstract: This week we experimentally determined the rate constant k for the reaction 2HCl (aq) +Na2S2O3 (aq) → S (s) + SO2 (aq) + H2O (l) + 2NaCl (aq). In order to do this the average reaction time was recorded in seconds during two trials. The data from the experiment shows this reaction is in the first order overall: rate=.47s-1 [HCl]0 [Na2S2O3]1. These findings seem to be consistent with the expected results
Figure 2: The absorabancy spectrum shows how absorbent the photosynthetic pigments are at different wavelengths of light. Note: Green light is between 500 to 570 nm and red light is between 630 to 720 nm.
The color that was chose to be shined through the sample was purple. The spectrophotometer was set at a wavelength of 400nm to represent the purple color. It was zeroed using the blank meaning the spectrophotometer read zero as absorbance amount. The blank consisted of 5mL of water and 2.5 mL AVM and it was placed in cuvette. A solution with a known concentration of 2.0x10-4 M was used in the spectrometer. For this solution, 5 mL of the solution with 2.5 mL of AMV was placed in the cuvette. The cuvette was placed inside of spectrophotometer and the amount of absorbance was recorded. This procedure that involves a solution with a known concentration was repeated for the concentrations:1.0x10-4 M,5.0x10-5 M,2.0x10-5M, and1.0x10-5M.A unknown solution absorbance was measured by putting 5 mL of unknown solution with 2.5 mL AMV in a cuvette. The cuvette was placed in the spectrophotometer and the amount of absorbance was recorded. The procedure that deals with the unknown solution was repeated 2 more times with the same solution and the same amount of solution and AMV. The average of the three unknown solution was calculated and the concentration of the unknown solution was
At equilibrium, the rate of decomposition of N2O4 is equal to the rate of combination of NO2. As the NO2 increases, then it starts declining as NO2 starts combining to form N2O4. This is called reverse reaction. The physical characteristic for this reaction is that the colour changes from colourless, d...
2. Put the test tube inside a beaker for support. Place the beaker on a balance pan. Set the readings on the balance to zero. Then measure 14.0g of KNO3 into the test tube.
If a substance has color, then you can determine its concentration by light absorption which is when light is being taken up by an object or spectrum. The Beer-Lambert Law is commonly used to find the absorbance (A) of light in a solution by multiplying the molar absorption coefficient ( ε ) ( how well a chemical absorbs light at a given wavelength ), the concentration ( C ) and the path of the light through the sample solution ( l ). The equation for this relationship is “ A=εCl ”. The color of the solution is determined by the color of light the molecules do not absorb, so, say if you had a blue colored solution, then the color of light will be orange. This is because the highest molar absorption coefficient for blue dye falls around 620 nanometer which is the orange part of the visible electromagnetic spectrum.
will result in an increase in the speed of the rate of reaction it has
A cuvette was filled 3/ 4ths of the way and the absorbance measured in a spectrophotometer. The data was compiled as a class and recorded. The Spectrophotometer was blanked using a test tube of distilled water.
2) Mirror image rule - The absorption spectrum is a mirror image of the emission spectrum for many fluorophores. This is known as the mirror image rule.
The purpose of the experiment is to study the rate of reaction through varying of concentrations of a catalyst or temperatures with a constant pH, and through the data obtained the rate law, constants, and activation energies can be experimentally determined. The rate law determines how the speed of a reaction occurs thus allowing the study of the overall mechanism formation in reactions. In the general form of the rate law it is A + B C or r=k[A]x[B]y. The rate of reaction can be affected by the concentration such as A and B in the previous equation, order of reactions, and the rate constant with each species in an overall chemical reaction. As a result, the rate law must be determined experimentally. In general, in a multi-step reac...
Varying the n value carries out the experiment. Absorbencies of each of the ZLn complexes are obtained. The sum of the concentrations of the metal, Z, and the ligand, L, are kept equal. With the ratio of the ligand to the metal in the solution with the maximum absorbance for the ZLn complex, the value of n can be determined as well as the composition of ZLn.
The relationship between light intensity varies inversely with the square of the distance holds truth in real-life situations and or under laboratory conditions.