Preview

determining of equllibrium constant

Good Essays
Open Document
Open Document
1133 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
determining of equllibrium constant
LAB REPORT 4 DETERMINING AN EQUILIBRIUM CONSTANT CAUSION
1. Potassium thiocyanate (KSCN) is hazardous
2. Wear protective material before performing the experiment.
INTRODUCTION
This experiment outlines the techniques necessary to determine the equilibrium constant for the formation of an iron(III) thiocyanate complex ion (FeSCN2+) from Fe3+ and SCN- . The quantitative preparation of several solutions and subsequent measurement of the solution absorbance using a spectrophotometer are the techniques that will be used in this experiment. The absorbance measurement gives the concentration of FeSCN2+. The concentrations of Fe3+ and SCN- are obtained as the difference between the initial concentration and the concentration consumed by the formation of the FeSCN2+. The combined concentrations will be used to calculate an equilibrium constant for the formation of the complex.
The reaction for the formation of the dark red FeSCN2+ complex ion is very simple
OBJECTIVES.
The purpose of this lab is to experimentally determine the equilibrium constant, Kc, In this laboratory, we will determine the Equilibrium Constant for the reaction between the Ferric Ion (Fe3+) and the Thiocyanate Ion (SCN-) which produces Ferric Thiocyanate Ion (Fe(SCN)2+): Fe3+(aq) + SCN-(aq) Fe(SCN)2 (aq)
MATERIALS
1. Cuvette 2. Pipet 3. Genesys 20 spectrophotometer 4. Dilute nitric acid, HNO3 5. Iron Nitrate, Fe(NO3)3 6 . Potassium thiocyanate, KSCN 7. Thermometer 8. Tissues 9.Protective devices
PROCEDURE OR METHODS
In Part A of the lab, I prepared six solutions – including a reference solution (known concentration) and a series of five test solutions (varied in concentration of SCN– (aq)). In Part B of the lab, I measured the absorbance of the solutions using a Spec 20. After collecting the data, I calculated the unknown equilibrium concentrations of the

You May Also Find These Documents Helpful

  • Good Essays

    Equilibrium Reaction

    • 615 Words
    • 3 Pages

    In this experiment, equilibrium will be examines in the reaction beteween the iron (III) ion and the thiocyanate ion:…

    • 615 Words
    • 3 Pages
    Good Essays
  • Satisfactory Essays

    Add 1/2 drop 0.1 M potassium ferrocyanide solution to tube 4. A deep blue precipitate will form because of the presence of iron (II) and iron (III) ions. This precipitate is iron (III) hexacyanoferrate (II). As the Iron (II) in test tube 1 is slowly oxidized into iron (III), it will begin to turn darker blue.…

    • 351 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    post lab of cucl2

    • 732 Words
    • 3 Pages

    II. Purpose: The purpose of this lab is to see how iron reacts with a copper (II) chloride solution.…

    • 732 Words
    • 3 Pages
    Good Essays
  • Good Essays

    Objective: The goal for this lab was to take the unknown solution and determine its ions.…

    • 1128 Words
    • 5 Pages
    Good Essays
  • Good Essays

    Reagent Added | Stress (Ion Added) | Colour Observation | Direction of Equilibrium Shift | NaOH (Step 5) | OH⁻ | Green | Left | NaOH (Step 6) | OH⁻ | Blue | Left | HCl (Step 3) | H⁺ | Green | Right | HCl (Step 4) | H⁺ | Yellow | Right | Part II: Equilibrium Involving Thiocyanatoiron (III) Ion Table 2 Reagent Added | Stress (Ion Added) | Spectator Ion | Observation | Direction of Equilibrium Shift | KCl | None | K⁺, Cl⁻ | No Change | No Change | Fe(NO₃)₃ | Fe³⁺ | NO₃⁻ | Solution Darkens | Right | KSCN | SCN⁻ | K⁺ | Solution Darkens | Right | NaOH | OH⁻ | Na⁺ | Solution Lightens ppt.…

    • 605 Words
    • 3 Pages
    Good Essays
  • Better Essays

    Copper In Brass Lab

    • 1053 Words
    • 5 Pages

    50 mL of concentrated nitric acid was measured in a graduated cylinder, 20 mL of which was transferred to the 80mL test tube. This test tube was placed in the Erlenmeyer flask with enough water covering at least 2 cm of the test tube. The coiled copper wire from earlier was cautiously placed into the test tube. The fume hood was lowered to prevent any inhalation of the toxic gas emitted from the exothermic reaction. The remaining nitric acid (HNO3) was slowly added during the dissolving of the copper wire.…

    • 1053 Words
    • 5 Pages
    Better Essays
  • Good Essays

    Enzyme Activity Lab Report

    • 1074 Words
    • 5 Pages

    Test tube one 1was filled with 5.0mL of buffer, 2.0mL of H2O2, and 1.0 mL of guaiacol. Tube 1 will be to calibrate the spectrometer. Tube 2-3 will be filled with Dil 0.25, tube 2, 4, 6 & 8 will contains 2.0 of 10mM H2O2 and 1.0 of 25mM of guaiacol. Tube 3 will contain 4.75 of 0.1 Buffer in mL and 0.25 of enzyme extract in mL. Tube 4-5 will be filed with Dil 0.5, but tube 5 will contain 4.5 of 1.0 Buffer in mL and 0.5 of enzyme extract in mL. Tube 6-7 will be filled with Dil 1.0, for instant tube 7 will contain 4.0 of 0.1 Buffer in mL and 1.0 enzyme extract in mL. Tube 8-9 will be filled with Dil 2.0; in addition tube 9 will contain 3.0 of 0.1 Buffer in mL and 2.0 of enzyme extract in mL. After we were done, we turned the spectrophotometer one and let it warm for about 5 minutes, we set the wavelength to 500nm we set it to a point that we could only read the absorbance until 1.999. We took a cuvette rack and placed about 5 cuvette tube. We took a clean cuvette and transfer all the contents of the tube 1 into the cuvette and wipe the outside with a kimwipe and insert the cuvette into the sample holder. After doing the previous step we turn the 100% transmittance control knob and control it until the reading said…

    • 1074 Words
    • 5 Pages
    Good Essays
  • Good Essays

    Iron and Cupric Sulfate

    • 851 Words
    • 3 Pages

    Iron powder will react with cupric sulfate in a one­to­one ratio (1 mole to 1 mole). The…

    • 851 Words
    • 3 Pages
    Good Essays
  • Powerful Essays

    where [A] represents the concentration of ascorbic acid and [B] represents the concentrations of [Fe(CN)6]3- at time t. For this experiment we will use an integrated rate law in the form of:…

    • 1174 Words
    • 5 Pages
    Powerful Essays
  • Good Essays

    Chem Lab 19A

    • 531 Words
    • 3 Pages

    2) When you add 6.0M NaOH into the iron (III) thiocyanate ion equilibrium system, the concentration of Fe3+ ion decreases. This causes the equilibrium system to shift to the left (reactant) side. This is why the solution becomes lighter yellow. Fe(OH)3 is also formed during the experiment.…

    • 531 Words
    • 3 Pages
    Good Essays
  • Good Essays

    Cathy Notes

    • 1473 Words
    • 6 Pages

    Solutions containing NH3, CO32–, Cl–, I–, PO43–, and S2O32– ions were added to equal proportions of a silver nitrate solution, which contained the complex ion Ag(H2O)2+. All of the added solutions were also clear and colorless.…

    • 1473 Words
    • 6 Pages
    Good Essays
  • Better Essays

    Anions Lab

    • 1345 Words
    • 6 Pages

    Purpose: The purpose of this lab is to identify the presence of cations and anions in four unknown solutions by identifying whether they are copper, silver, iron, or chloride ions which is done by adding sodium hydroxide, solid copper, silver nitrate, and potassium thiocyanate to the solutions and analyzing the chemical reactions.…

    • 1345 Words
    • 6 Pages
    Better Essays
  • Good Essays

    Rdr4 Chemical Equilibrium

    • 1657 Words
    • 7 Pages

    A blood red solution was achieved which indicates the presence of Fe3+ ions. Lastly, for the Ag+ test, the HCl was added to the supernate shown in the ionic equation below:…

    • 1657 Words
    • 7 Pages
    Good Essays
  • Powerful Essays

    | |purple to pink |purple to pale |purple to pale |purple to pale pink| |…

    • 969 Words
    • 4 Pages
    Powerful Essays
  • Powerful Essays

    In this experiment we needed again to gain crystals. The increased affinity towards complex formation exhibited by metal ions with an unfilled d-shell is related to the crystal field stabilization of such compounds and furnishes an explanation of what is the basis of the so-called Irving-Williams rule. The orbital degeneracy of the ground term determines the symmetry of the configuration and is thus responsible for irregularities in the complexity constants. In this experiment, we want to show how many grams of thiourea that we gain. The first thing that we do was mixing the thiourea and anhydrous methanol we dissolved the compound and put on the hot to warmed add a few drops of carbon tetra chloride-octanol when you see that the crystals filter it. After this things put it inside the oven and left it to an hour after an hour we weigh it again and solved for the percentage recovery.…

    • 1110 Words
    • 5 Pages
    Powerful Essays