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IB1 Chemistry Topic 6: Kinetics Rates of reaction

IB1 Chemistry Topic 6: Kinetics Rates of reaction. Why are some chemical reactions over in seconds while others take years?. Image : https://en.wikipedia.org/wiki/ Explosion , https://en.wikipedia.org/wiki/ Rust. Rate of reaction.

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IB1 Chemistry Topic 6: Kinetics Rates of reaction

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  1. IB1 ChemistryTopic 6: Kinetics Rates of reaction

  2. Why are some chemical reactions over in seconds while others take years? Image: https://en.wikipedia.org/wiki/Explosion, https://en.wikipedia.org/wiki/Rust

  3. Rate of reaction the increase in the concentration of a product or decrease in the concentration of a reactant with time moldm-3s-1

  4. Measuring rates • mass or volume changes as a gas is evolved • colour changes (using a spectrometer) • pH changes • conductivity changes for ionic solutions

  5. Rate of reaction Mg and HCl using a gas syringe • Use a 4cm piece of Mg and 25cm31M HCl • Find the mass of the magnesium • Measure the volume of gas at 10second intervals • Calculate the concentration of the HCl • Draw a graph of concentration against time • Calculate average rate • Calculate instantaneous rate from gradient of graph

  6. Collision theory • particles must collide • in the right orientation • with enough energy (minimum energy is activation energy) Image: http://en.wikipedia.org/wiki/Traffic_collision

  7. Reaction rates in solution Image: http://www.chemguide.co.uk/physical/basicrates/concentration.html#top

  8. Effect of surface area

  9. Effect of surface area

  10. Effect of temperature on reaction rate HCl(aq)  +   Na2S2O3(aq)NaCl(aq)     +      SO2(g)   +      S(s)  +  H2O(l)

  11. Maxwell-Boltzmann distribution Image: http://chemwiki.ucdavis.edu/Physical_Chemistry/Kinetics/Rate_Laws/Gas_Phase_Kinetics/Maxwell-Boltzmann_Distributions

  12. Activation Energy, Ea the minimum energy required to start a chemical reaction. Image: http://en.wikipedia.org/wiki/Activation_energy

  13. Catalysts A catalyst increases the rate of a chemical reaction, but is not used up during the reaction. Catalysts reduce the activation energy. Transition metals are often useful catalysts. Enzymes are catalysts in biological systems.

  14. What sank the Kursk? • The Kursk torpedoes contained hydrogen peroxide , and one theory suggests this might have caused the explosion. • Plan an investigation into the catalysis of H2O2 Image: http://en.wikipedia.org/wiki/File:Kursk_wreck.jpg

  15. Links • http://phet.colorado.edu/en/simulation/reactions-and-rates • http://en.wikipedia.org/wiki/Russian_submarine_K-141_Kursk • http://www.youtube.com/watch?v=iTcogT-m2mk • http://www.rsc.org/education/teachers/resources/aflchem/resources/63/index.htm

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