2) Percent recovery for isolation of benzoic acid % Recovery = mass of recovered material _________________________________ x100% mass of starting material = (0.43/1.01) x100% = 42.57% That concludes that the percent recovery is 42,57%. 3) Percent recovery for isolation of hydroquinone dimethyl ether % Recovery = mass of recovered material _________________________________ x100% mass of starting material = (0.16/1.01) x100% = 15.84% That concludes that the percent recovery is 15.84%. Table 2: : Experimental IR peaks compared to literature IR peaks for Benzoic acid Functional groups | Experimental peak (cm-1) | Literature peak (cm-1) | O-H | 3407-2563 | 3400-2564 | C=O | 1689 | 1689 | C-H |
The apparent reaction rate was calculated using the equation, kapp= (1/∆t) x ([S2O32-]/[S2O82-]) which resulted in apparent rate constants of 5.66 x 10-5 s-1, 6.1958 x 10-5 s-1, 6.0356 x 10-5 s-1. The actual concentration was calculated using the basic chemical equation, C1V1 = C2V2. In order to find the order of reaction a a graph of log rate vs. log [S2O82-] was drawn, and was found that the results gave a zero order reaction But in reality the reaction order in [I-] and [S2O82-] is in first order each, although [I-] is kept at a constant volume throughout the reaction therefore the overall reaction is pseudo- first order. -d [S2O82-] = kapp [S2O82-] Dt In the second part the rate constant was found using the equation k = (1/∆t) x ([S2O32- ]/[Iodine][S2O82-]). Where it resulted to values of 3.990602 x 10-3 s-1, 4.653278 x 10-3 s-1, 5.944044 x 10-3 s-1, 7.499958 x 10-3 s-1, 7.499958 x 10-3 s-1, 9.84554 x 10-3 s-1, for flasks 4, 5, 6, 7, 8.
Experiment 7 Formula of a Complex Ion by the Continuous Variation Method Objective: To determine the formula of a complex ion by the continuous variation method. Procedure: Refer to laboratory manual. Results and Calculations: 1. Calculate the molarity of both CuCl2 solution and the ethylenediamine solution. Number of moles of CuCl2 used = [pic] =[pic] = 0.127 moles Therefore, Molarity of CuCl2 = [pic] = [pic] = 0.063 mol/dm3 Number of moles of ethylenediamine used = [pic] =[pic] = [pic] = 0.1 mole Therefore, Molarity of ethylenediamine = [pic] = [pic] = 0.05 mol/dm3 2.
37 Rb Rubidium 85.4678 Atomic Number: 37 Atomic Weight: 85.4678 Melting Point: 312.46 K (39.31°C or 102.76°F) Boiling Point: 961 K (688°C or 1270°F) Density: 1.53 grams per cubic centimeter Phase at Room Temperature: Solid Element Classification: Metal Period Number: 5 Group Number: 1 Group Name: Alkali Metal What's in a name? From the Latin word for deepest red, rubidus. Say what? Rubidium is pronounced as roo-BID-i-em. History and Uses: Rubidium was discovered by the German chemists Robert Bunsen and Gustav Kirchoff in 1861 while analyzing samples of the mineral lepidolite (KLi2Al(Al, Si)3O10(F, OH)2) with a device called a spectroscope.
Gallium, indium, aluminium, boron. Indium, gallium, aluminium, boron. JSC 2006, Physical Science [Turn over 2 5 The combination of protons, neutrons and electrons for a neutral atom of magnesium, 24 Mg, is: protons electrons A 10 14 11 B 11 13 12 C 12 12 12 D 6 neutrons 12 12 10 Which structure represents an atom of the noble gas in the first period. e e e pn np np pn n np p e e e e e e A 7 e e e pnn pnn npp e B C e e e D A mixture containing a soluble salt, sand and iron filings, can be separated into its components using techniques: R: use of
| 6.99V | 0.14A | 7. | 8.00V | 0.16A | 8. | 9.03V | 0.18A | 9. | 9.98V | 0.20A | 10. | 18.01V | 0.36A | 50-ohm Resistor | V drop | I through | 1.
Main – group metals usually for one cation (positive ion). In a binary ionic compound the metal (cation) is named first. Then the nonmetal (anion) is named, and the suffix -ide is added. To create the formula, you switch the charges, and that tells you how many of each element you will need. For example: Cation Anion Formula Name of Compound Ba2+ I- Ba2+ I- Barium Ion Iodide Ion BaI2 Barium Iodide Type 2: Binary Ionic Type 2 Binary Ionic compounds consist of a metal and a nonmetal.
Practical 5 – Heavy Metals by Absorption Spectrometry Contents Aim - 1 Introduction 1 Procedure 2 Pre-laboratory exercises 2 Results and discussion 3 Conclusion 3 References 3 Aim – The aim of this practical is to determine the concentrations of each of Cu, Pb and Cd in an unknown solution with the use of Atomic Absorption Spectrometry. Introduction Atomic Absorption Spectrometry or ‘AAS’ is a spectrophotometric analysis technique that allows for both quantitative and qualitative determination of most elements. Each elemental metal absorbs ultraviolet light at a specific wavelength when excited by heat; this is the basis of atomic absorption spectrometry The procedure involves passing known concentrations of the element in solution through a nebulizer forming a mist. This mist is then aspirated into a flame forming gaseous atoms, elementary ions and molecular species. A focused beam of ultraviolet light at a specific wavelength is directed at the sample, reduction in the intensity of the light is then measured and converted to absorbance.
* To improve mathematical skills. The stability constants of the tri-iodide ion was found to be Introduction: Non-polar octamethylcyclorasiloxame, volasil 244, and polar potassium iodide are mixed together and the iodide distribution between them was examined. Volasil 244 is a source of I2, potassium iodide is a source of I- and in equilibrium they are I2 + I- I3-. The equilibrium or stability constant is denoted by [I3-]/[I2][I-]. I2 is the only species that is undergoing distribution.
For the laboratory an unknown steel was used and the nickel content was determined using a gravimetric method and by exploiting the chemical properties of the compounds and solutions. Nickel was precipitated from an alkaline medium with the chelating agent dimethylglyxomine. Chelating agents are essetentially chemicals that combines with a metal to form a chelate Tartaric acid (see Figure 1), for example, is used to form a complex with Iron (III) to prevent its precipitation. The tartrate ion (see Figure 2) forms a complex with iron (III) in slightly alkaline solutions as: Fe2O3·xH2O The product formed by the tartaric acid interference is freed from moisture by drying at 110 degrees Celcius. When working dimethylglyoxamine, carefull attention has to be taken when adding the chemical because both an excess amount and insufficient amount of the organic compound will have an adverse effect.