Design - Potassium Dichromate Essay Example for Free

Design Potassium Dichromate EssayIntroductionThe answer that is carried out in this design functional is between acidified Potassium dichromate and squeeze fleece. The reaction is a redox reaction. A Redox reaction (a short way of saying reduction-oxidation reaction) is the simultaneous conveyancing of electrons between multiple substances. The oxidation numbers or the oxidation state of atoms is changed through the process of oxidation or reduction. Reduction is where electrons ar gained to the reaction and oxidation is when electrons argon lost in a reaction between substances. In this experiment compact (or Fe) is losing two electrons meaning it undergoing oxidation. Potassium Dichromate is gaining electrons meaning it is undergoing reduction. The Iron is the Reducing agent because it gave electrons to the Potassium Dichromate. The Potassium Dichromate is the oxidising agent because it took electrons from the iron.This experiment will attempt to prove the redox reactio n through experimentation.Redox half equationsx3 ( Fe Fe2+ + 2e- )Cr2072- + 14H+ + 6e- 2Cr3+ + 7H2OCr2072- + 14H+ + 3 Fe 2Cr3+ 7H2O 3Fe2+AimThe aim of this experiment is discover the relationship between the temperature (20C,25C,30C,35C,40C) of the reaction between acidified Potassium Dichromate and Iron victimisation a water bath on the rate in which the acidified Potassium Dichromate and Iron react and change garble from yellow to fatal purple.The single-handed variable in this experiment is the temperature. The reaction will be carried out at a range of temperatures. (20C,25C,30C,35C,40C) . The reaction will be carried out in a water bath. The temperature will be rated with an electronic thermometer and will be measured every 10 seconds to make sure the water bath is at a constant temperature in each trial.The dependent variable is the time it takes for the reaction between Potassium Dichromate and Iron wool to get under ones skin to completion or to turn from yellow t o green. Time will be measured with a digital stop respect.Independent variableIndependent variable browse (C 0.1C)How it is measuredHow they are changedTemperature20,25,30,35,40Electronic thermometerChanging temperature of water bathDependent variableDependent VariableHow it is measuredProblemsTimeStop watch controlled by humanReaction timeConstant variablesConstant variablesMeasurementHow they are kept constant /monitoredAmount of H2SO4 used20ml 0.1The same meter piston chamber was usedAmount of Potassium Dichromate used20ml 0.1The same measuring cylinder was usedStirring speedSlow but constantcharismatic stirrer wasnt able to be used in water bath, so I manually stirred the solution slow and constantlyMass of wool0.295g 0.305g 0.01Mass of iron wool was kept as close as possible in each testSurface area of wool6cm3 wool was squeezed into cube shape 1cmx1cmx1cmType/brand of woolSuperior manufactures ltdSame box of Iron wool is usedAir temperature19.0C 0.1CTests are carried out on same day tautness of sulphuric acid2.0 molSame bottle is used in each testConcentration of chiliad dichromate0.1 molSame solution is used in each testColourYellow- dark greenA pilot with dark green colour is used to compare to the colour change in the trialsHow to ensure reliability of resultsTo ensure the reliability of results the temperature of the water bath and the reaction are measured very frequently (once a min). The chemicals came from the same containers as to keep concentration consistent. I did a pilot test first to see what colour I am looking for. This beaker of dark green liquid is then used to compare with the colours in the trials so I know when the reaction has come to completion.Equipment1) 5x 20ml Sulphuric acid-2.0mol2) 5x 20ml Potassium Dichromate- 0.1mol3) 5x 100ml Beakers4) 1x Digital stop watch 0.5 sec5) 1x Electronic thermometer 0.1C6) 1x large water bath 0.1C7) Approximately 2g Iron wool- split into 5x 0.300g -1cm3 -cubesMethod1) Gather all the equipment that is listed in the equipment list provided above and prepare a table like the one shown on the following page.2) second set your water bath at 20C. Weigh the iron with electronic scales (0.001g) wool fashioning and modify its mass to make it 0.300g or as close as you can get. Squeeze the iron wool so that the wool is approximately 1cmx1cmx1cm. This makes the surface area constant over the trials.3) Next measure 20ml with a 50ml 1ml measuring cylinder of 0.1mol Potassium dichromate. Pour it into a 100ml beaker making sure to pour all drops into the beaker. Measure 20ml of 2.0mol sulphuric acid with a 50ml 1ml measuring cylinder. Pour it into the same 100ml beaker as the potassium dichromate.4) Measure the temperature of the water bath the an electric thermometer making sure it is 20C. When certain the temperature is constant place the beaker with the potassium dichromate and sulphuric acid into the water bath. Make sure as much of the beaker is under the water as possible but ke eping adequacy above not to let any of the water in. Get someone else to hold the beaker down if required.5) Measure the temperature of the potassium dichromate and sulphuric acid making sure the temperature is exactly 20C. When satisfied this is accurate hold the stop watch in one hand and the 0.300g 0.001g iron wool in the opposite hand. Place the iron wool in the beaker and simultaneously push the start button on the digital stop watch. The colour should change from yellow to a dark green colour. As soon as you are satisfied the colour has changed to the dark green colour push the stop button on the digital stop watch. Record this time in your pre prepared data table.6) Next repeat steeps (2-5) 5 times with the same chemicals. These will be the pentad trials.7) Repeat steps (2-6) 5 times but now change the water bath temperature. The range of temperatures are ). Record all the data in the table you have prepared.Data TableRaw data table showing the effect of a change on temper ature on the rate in which the reaction between acidified Potassium Dichromate and Iron wool occurs.