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# Rate of reaction for limestone and citric acid.

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rate of reaction of limestone with citric acid - coffee machine de-scaler,

rate of reaction of limestone with citric acid - coffee machine de-scaler,

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• 1. Friday, 12 July 2013
• 2.  Chemical reactions take place at very different rates – some are very fast (like explosions) and others may take months or years to proceed.  In a chemical reaction which produces a gas the rate can be measured by determining the volume of gas produced as time passes.  Limestone produces carbon dioxide gas when it reacts with an acid. The rate of production of carbon dioxide can be measured in several ways.
• 3.  In this experiment the reagents are calcium carbonate (limestone) and citric acid.  The products are calcium citrate, carbon dioxide gas and water.  The rate of the reaction is measured by measuring how fast the carbon dioxide gas is produced.  The limiting reagent is the amount of citric acid. This is the first reagent to be use up.
• 4. Measure volume on a measuring cylinder
• 5. Rate of reaction experiment Time (s) Volume of Carbon Dioxide (ml) 0 0 30 16 60 25 90 31 120 34 150 35 180 36 210 36 240 36
• 6.  We can record the rate using this relation|:  Rate of reaction = change in recorded property time for the change  Actual rate is the gradient of the line of the product concentration versus time graph.  Average rate is the gradient of the line joining the two point in time over which the rate is being measured.
• 7. 0 5 10 15 20 25 30 35 40 0 50 100 150 200 250 300 Volumeofhyrdoger Time (s) Rate of reaction experiment. Rapid reaction here Reaction slows down here. Reaction stops here
• 8. 0 5 10 15 20 25 30 35 40 0 50 100 150 200 250 300 Volumeofcarbondioxide Time (s) Rate of reaction experiment. Rate of reaction experiment Volume of Hydrogen (ml) Rate at the start of the reaction.
• 9. 0 5 10 15 20 25 30 35 40 0 50 100 150 200 250 300 Volumeofcarbondioxide Time (s) Rate of reaction experiment. Rate of reaction experiment Volume of Hydrogen (ml) Average rate of reaction between 0s and 200s.
• 10.  Calculate the number of moles of carbon dioxide produce in experiment 1 above.  Volume of carbon dioxide = 36ml  1 mole of carbon dioxide = 24000 ml  Number of moles of carbon dioxide  = 36 ÷ 24000  = 0.0015 moles
• 11.  In this experiment calcium carbonate reacts with ethanioc acid (acetic acid).  The rate of reaction is measured by collecting the carbon dioxide gas produced in a gas syringe.  The results can be processed in the same way as those for experiment 1.
• 12.  In this experiment calcium carbonate reacts with citric acid.  The rate of reaction is measured the mass of the remaining chemicals.  The loss in mass is due to the escaping carbon dioxide gas.  The results can be processed in the same way as those for experiment 1 except that the factor changing is the mass and not the volume.
• 13.  Concentration  The higher the level of concentration (or pressure in gases) the faster the reaction.  This is due to increased collisions between reacting particles.
• 14.  Surface area in solids  The larger the surface area of a solid the faster the reaction. Finely divided substances have much larger surface areas than large chunks of a solid.  This is due to increased collisions between reacting particles.
• 15.  Temperature  The higher the temperature the faster the reaction.  This is due to increased and more energetic collisions between reacting particles.  A 10oC rise in temperature often results in a doubling of the reaction rate.
• 16.  Only molecules with enough activation energy will react to form the products.
• 17.  Catalysts  Catalysts increase the rates of chemical reactions.  This is due a lowering of the activation energy for the reaction.  Catalysts are not consumed in the reaction so in theory they can be used over and over again. In practice they are often contaminated and/or some is lost in a process.
• 18.  Scientists assume all gases are made of particles in constant random motion. They have regular elastic collisions with other molecules.  Gas molecules collide with the walls of their container and exert pressure but do not lose energy in their collisions and do not attract other molecules.  The volume of actual gas molecules in a container is negligible and their average kinetic energy is proportional to the temperate (Kelvin).
• 19.  http://ie.dynapipe.co.uk/how-to-remove-limescale.htm  http://en.wikipedia.org/wiki/Limescale  http://www.movia.ro/decalcifiere_eng.html  http://www.thor.com/view.asp?id=20130408120303AAmFq15  http://www.newworldencyclopedia.org/entry/acetic_acid  http://www.newworldencyclopedia.org/entry/Citric_acid  http://en.wikipedia.org/wiki/Sulfamic_acid  http://www.lihuasz.com/news/what_is_sulfamic_acif-en.html  http://www.yangheng.com/zycp08.htm  http://uk.answers.yahoo.com/question/index?qid=20130414114029AATzCWd  http://www.howtocleanthings.com/appliances/how-to-clean-coffee-maker.htm  http://chowhound.chow.com/topics/360882  http://scottiestech.info/2009/04/22/descaling-appliances-which-acid-is-best/  http://www.ceragol.com/en/products/premium-descaler/descaling/  http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Acetic_acid.html  http://en.wikipedia.org/wiki/Calcium_carbonate  http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Calcium_carbonate.html