IB Chemistry Lab - Determining the Presence of Chemicals

Determining the Presence of Pb2+, Ag+ and Hg22+ Date Performed: 3/12/08 The molecular equations that involve Pb2+, Ag+ and Hg22+ with the addition of HCl can cause the formation of precipitate. These elements can be precipitated and separated with HCl and the addition of other ions. However, if HCl is in excess, the result may be the formation of soluble complex anions. Lead, mercury (I) and silver can be separated and identified by the addition of CrO4, the addition of NH3(aq) and acidifying the liquid using HNO3 respectively as well. Planning A Question: According to the composed equations from above, will Pb2+, Ag+ and Hg22+ be present in the unknown sample by using certain chemicals to separate these ions? The goal of this lab is to determine the presence of Pb2+, Ag+ and Hg22+ by adding HCl and other chemicals to see if precipitate forms. The color of the precipitate will indicate the presence of these cations. A centrifuge will be used in order to mix the solutions and separate the supernate and the precipitate. Hypothesis: I believe that Pb2+, Ag+ and Hg22+ will be present in the unknown if the composed equations are correct. According to the equations, a solid forms after the addition of certain chemicals such as ammonium. Planning B Variables: - - An unknown sample - A centrifuge machine - Three small test tubes - About 500 mL of distilled water -

  • Word count: 667
  • Level: International Baccalaureate
  • Subject: Chemistry
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Synthesis of FeS

SYNTHESIS OF FeS Seren Sapmaz 582 ATC Purpose: To synthesize iron (II) sulfide from iron and sulfur. Materials: * * Iron filings * Sulfur powder * A test tube * Test tube holder * Bunsen burner * A magnet * An equal arm balance * A box of matches * Ethyl alcohol * A set of masses Procedure: . Weigh 2.1g of iron powder and 1.2g of sulfur powder. Put them in different places. 2. First take a magnet and approach to iron fillings. The magnet will attract the iron filings. 3. Then take a little bit sulfur and put in into water. Observe what you see. Sulfur dissolves in water. 4. After that put the iron filings and rest of sulfur in a test tube and mix well. 5. Hold the test tube with the holder in inclined position, and heat gently. Take away the burner as soon as the mixture starts to glow. When reaction stops, heat it strongly for two more minutes. 6. Take the substances out of the test tube onto the watch glass. If necessary, break the test tube to remove the contents from it. 7. Watch the substance formed. Examine the effect of the magnet on the substance. Is it attracted by magnet? Crush the substance. Add a spatula measure of the substance to about 10cm3 of ethyl alcohol. Close the test tube with a stopper and shake it. Does it dissolve? 8. Remember that iron is attracted by magnet and sulfur dissolves in ethyl alcohol. Did the properties of

  • Word count: 453
  • Level: International Baccalaureate
  • Subject: Chemistry
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Dissolving and Energy Changing

SPH Dissolving and Energy Changing Science Experiment Sarah Harefa 10.4 Solutions Initial Temperature (°C) Final Temperature (°C) NH4NO3 22 9 KCl 21 9 Na2CO3 22 9 NaNO3 20 8 KNO2 21 8 NaOH 21 32 Temperature Changes of Dissolved Solutions in Distilled Water Evaluation: The overall outcome of the experiment is really good. We learn new things about endothermic and exothermic reactions and be acquainted with lab more. However during the experiment, there are few flaws groups keep making. First of all, the thermometer flaw; we must record the initial time of the water to know what type of reaction is occurring and read thermometer in on eye level. It's very crucial if we groups keep making the flaws, the experiment will become unreliable. Secondly, instruments hygiene; we must clean thermometer with water and dry it off with tissues to avoid other solutions to be contaminated and clean the instruments afterward with clean brush and soaps to avoid serious damage. Conclusion: This experiment thought us more about exothermic and endothermic reaction. Solutions such as NH4NO3, KCl, Na2CO3, NaNO3, and KNO2 are all endothermic reaction as the Final temperature fall by an average of 2.6°C from the initial temperature of 20-22°C. It proves that the energy from surrounding is absorbed to into the system which is the solutions and breaks the chemical bonds.

  • Word count: 257
  • Level: International Baccalaureate
  • Subject: Chemistry
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Crude Oil

Crude Oil Why does Crude Oil cause such excitement? Crude Oil is a fossil fuel, meaning that it entirely made up of the remains of plants and animals that lived millions of years ago. Dead marine plants and animals would lay buried under the seabed, and eventually layer after layer of sedimentary rock would form on top. The remains couldn't rot away as there was no oxygen. Eventually the Earth's crust would increase heat and pressure, causing the remains to turn into oils and gasses. Since oils and gasses are much less dense than water they would rise up through the permeable rock, until they couldn't get further. This is called an oil trap as the impermeable layers of rock trap them under the Earth's surface, the rock they collect within the trap is usually called reservoir rock. Crude Oil mainly consists of complex hydrocarbon chains as well as other organic substances. Hydrocarbons are basically composed of different isomers hydrogen and carbon atoms. The amount of hydrocarbons depends on the type of oil, for example Heavy Crude Oil consists of mere 50% hydrocarbons while a lighter more valuable type can almost purely contain hydrocarbons. In simple terms, Crude Oil is a treasure trove of useful substances. Not only is Crude Oil used to produce fuel for cars, trucks, airplanes, boats and trains, but it is also used for a wide variety of other products including asphalt

  • Word count: 1761
  • Level: International Baccalaureate
  • Subject: Chemistry
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Fractioanl Distillation

FRACTIONAL DISTILLATION Seren SAPMAZ 582 ATC Fractional distillation: Is the separation of a mixture into its component parts, or fractions, such as in separating chemical compounds by their boiling point by heating them to a temperature at which several fractions of the compound will evaporate. Aim: To show the use of fractional distillation for the separation of liquid - liquid mixtures in which the boiling points of the components are similar. Materials: * * Heater * Thermometer * Water inlet-outlet * Distilling Flask, * Beaker * 4 Test Tube * Tripod * Acetone-Water-Alcohol mixture Procedure: * Start heating the homogenous mixture of acetone, alcohol and water. (at 30 degree) * Every 30 seconds take the temp. reading. * When the temp. starts almost constant collect the condensed liquid, save it in a test tube. (around 50o) * When the temp. begins to raise again taking temp. reading every 30 seconds. Keep heating the mixture. * When it gets constant again collect the liquid and keep it another test tube. (around 70o) * Then increase the degree to 6o. And collect the consented liquid around 80o . * Then collect the last liquid around 95o. Conclusion: * Test the volatility of each fraction of liquid collect at 4 different tubes. Write your observations. -In the first tube we saw acetone collected. Because acetone has the smallest boiling

  • Word count: 518
  • Level: International Baccalaureate
  • Subject: Chemistry
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Determining the activation energy of a reaction, By using the experimental data and the Arrhenius equation, the activation energy for the reduction of peroxodisulphate ions, S2O82-(aq) by iodide ions, I-(aq) in a clock reaction is found to be approximatel

Determining the activation energy of a reaction Data Collection Table 1: Raw data - time taken for the mixture to turn blue-black in colour Temperature/?±1 30 35 40 45 50 Reaction completion time/second ±1 52 99 76 46 44 Data processing Table 2: Processed results from Table 1 Temperature, T /K±1 K-1 Rate constant, K /dm3 mol-1 s-1 ln K 303 0.00330 0.00658 -5.02 308 0.00325 0.0101 -4.60 313 0.00319 0.0132 -4.33 318 0.00314 0.0217 -3.83 323 0.00310 0.0227 -3.78 Note: the rate constant, K is calculated as follows: Graph Note on graph: In this graph T is temperature in Kelvin and t is the time taken for the reaction to reach the blue-black colour stage. A R2 value is calculated in the graph above using Microsoft Excel. The R2 value - or the coefficient of determination, can be an indication of how closely the points relate to a line of best fit. It ranges from 0 to 1 with the latter indicating that the line of best fit can fully predict future points. The R2 value in this graph is found to be 0.9628, which is quite close to 1. This suggests that this linear line is a good fit of the points. Calculating the activation energy The Arrhenius equation states that, ln k = where k = rate constant A = Arrhenius constant E = activation energy R = Universal gas constant = 8.31 J k-1 mol-1 T = temperature in Kelvin This logarithmic

  • Word count: 1123
  • Level: International Baccalaureate
  • Subject: Chemistry
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The effect of the temperature on a reaction rate

The effect of the temperature on a reaction rate: I) Aim: Observe the effects of temperature on the reaction rate II) List of equipment: - 50 cm3 of sodium thiosulphate solution - 200 cm3 of water - 25 cm3 of hydrochloric acid - flask - cylinder - tripod - micro burner - stop clock - safety goggles - lab coat - a paper with a black cross on it - thermometer III) Method: We put 10cm3 of sodium thiosulphate solution and 40 cm3 of water in a flask at room temperature and then we put 5cm3 of hydrochloric acid and we time the reaction. We put the flask on a paper with a black cross on it. When we could not see the cross anymore, we have stopped the clock and note the time. We redo the same experiment with different temperature. To change temperature of the experiment we use a micro burner to heat the water and measure its temperature with a thermometer and then we put the sodium thiosulphate solution and the hydrochloric acid and we time the reaction. We do this processes 4 times. IV) Table of results: The rate of reaction => Temperature (°C) / time taken(s) The reaction and the temperature: Start temperature (°C) End temperature (°C) Average temperature (°C) Time of reaction (s) Rate of reaction (/s) 22 21 21.5 30 /130 26 25 25.5 85 /85 36 35 35.5 50 /50 45 42 43.5 44 /44 55 48 51.5 29 /29 V) Graph: There is

  • Word count: 508
  • Level: International Baccalaureate
  • Subject: Chemistry
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The aim of our experiment was to find the mass of acetyl salicylic acid in an aspirin tablet and compare it with the manufactures claim.

Chemistry Write up # 3: Analysis of Aspirin Tablets Table showing masses and measurements of chemicals in the experiment Description Value Unit Uncertainty Percentage Uncertainty Mass of aspirin tablets x4 .713 g ???? 0.058% Literature value/ manufacture's claim of salicylic acid in an aspirin tablet 300 mg Amount of NaOH added 25.0 ml 0.1?mL 0.4% Concentration of NaOH 0.998 mol dm-3 Concentration of sulphuric acid 0.0495 mol dm-3 Mols of NaOH 0.0250 mol Volume of sulphuric acid 7.28 cm3 0.1?mL .37% Table showing the volume of (0.0495 mol) sulphuric acid needed to neutralise the NaOH solution ml) Volumes Trials (ml) (ml) ± 0.1 Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Average Initial Volume (ml) ± 0.05 0.2 9.7 7.2 25.4 32.6 Final Volume (ml) ± 0.05 7.5 7.1 24.4 32.6 39.9 Change In Volume (ml) ± 0.1 7.3 7.4 7.2 7.2 7.3 7.28 ± 0.1 Observations: * When adding the sulphuric acid to the NaOH, indicator and salicylic acid during titration the colour changed from blue to yellow. * There was a strong smell when the aspirin and water was boiling. * The mixture in the volumetric flask still had solid clumps in it. This we discovered was part of the outside shell of the aspirin tablets. * A thin foamy layer formed on the meniscus of the mixture of the volumetric flask after it was

  • Word count: 1033
  • Level: International Baccalaureate
  • Subject: Chemistry
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Research Question Will increasing the temperature (C) of the rennin enzyme affect the rate of reaction (seconds) at which Pauls full cream milk solidifies?

High Level Chemistry Design Practical Investigate the effect of one factor on the chemical reaction of an enzyme Background Information Globular proteins which are called enzymes are produced inside the human body. Enzymes are organic catalysts which mean they have the role of speeding up chemical reactions. The role of enzymes is essential for most human body functions. Specific enzymes at specific locations within the human body attain specific abilities to aid chemical reactions. [1] In this experiment, the type of enzyme that will be used for testing is called rennin. Rennin is a type of enzyme that can be found in the stomach of humans and is produced by the stomach cells of humans. Rennin's specific enzyme ability is to transform milk into semi-solid particles. If milk was not coagulated (solidified), milk would just simply flow through the stomach and not be 'chemically' digested. [2] Normally, the human body temperature is 37°C and rate of reaction is most favourable at this temperature. [2] As with all enzymes, altering the temperature affects the rate of rennin and milk. According to the principles of Kinetic Theory, increasing the temperature would increase speed of particle collision and therefore increase the rate of reaction. [1] Contrary, decreasing the temperature would slow down the speed of particle collision so therefore the rate of reaction

  • Word count: 1510
  • Level: International Baccalaureate
  • Subject: Chemistry
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Energy content Cal/g

Objective: The purpose of this experiment is to burn samples of food and experimentally determines their energy content Cal/g. Introduction: Energy remains an essential element to living beings, humans cannot survive without it. In order to begin to grasp an understanding of just how much energy is required to allow the human body to operate, we can start by understanding the energy content contained within something as common as a fiery cheeto. Through burning of the food under a calorimeter, temperature can be gauged and the energy content in Cal/g can be quantitatively determined. Materials -one soda can - 50 ml graduated cylinder (+/-.5 ml ) - centigram balance - 1 Cork -ring stand and iron ring - 1 Paper Clip -wire mesh - Foil -thermometer (+/- .5°C) - samples of Chester's flaming fries Procedure: . Set up ring stand with wire mesh over the ring. 2. Obtain 1 soda can 3. Obtain 50.0 mL of tap water 4. Pour water into the can 5. Place can on the ring stand. 6. Push the paperclip into the cork so that it can support the sample of food. 7. Cover the paperclip/cork with aluminum foil. 8. Obtain a sample of food 9. Mass the sample of

  • Word count: 2006
  • Level: International Baccalaureate
  • Subject: Chemistry
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