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Rates of Reaction

Rates of Reaction. Adrian, Fraser, Roderick, Emma. Introduction. Define 1) Reaction -Indications 2) Rate of Reaction Influencing factors: -Concentration -Temperature -Catalyst. Objective. Determine how concentration, temperature and catalysts affect the rate of reaction.

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Rates of Reaction

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  1. Rates of Reaction Adrian, Fraser, Roderick, Emma

  2. Introduction Define 1) Reaction -Indications 2) Rate of Reaction Influencing factors: -Concentration -Temperature -Catalyst

  3. Objective • Determine how concentration, temperature and catalysts affect the rate of reaction

  4. Materials

  5. Safety Precautions • Wear safety goggles at all times • Long hair tied back • Wash hands before and after each experiment Third Experiment: Catalyst • Chemicals used are explosive • No open flames

  6. TEMPERATURE

  7. Experiment: Temperature • How does Temperature affect the rate of reaction? • Alka-Seltzer tablets in different temperatures of water

  8. Temperature: Procedure • Place 250 mL of water into a beaker • Record the temperature • Gently place the tablet into the beaker • Record the time taken to dissolve • Repeat for hot and cold water

  9. Temperature: Observations

  10. Temperature: Actual Affects • When the temperature of a substance rises, the particles gain energy • With more energy, the particles move faster • They then collide with the other substance at an increased rate • Less time for the reaction to occur

  11. Sources of Error • Temperature • Recorded values could be out • Exact Time • Hard to tell the tablet had completely dissolved

  12. Modifications for the Future For more accurate results: • Conduct the 3 trials at once • Add more temperatures to test

  13. Temperature: Conclusion • Temperature directly affects the rate of reaction. •  temperature =  particle movement •  particle movement =  collision •  collision =  rate of reaction • Opposite occurs for a decrease in temperature

  14. CONCENTRATION

  15. Concentration Experiment • Particle Collision theory: explains how reactions occur, and why there are different rates of reactions based on differences of characteristics

  16. Concentration Experiment • Concentration: the amount of a given solute in a solution • Concentration = number of moles / Volume of solution (L) • Unit = mol / L or M • Can also be calculated in Volume / Volume percentage. (Volume of solute / Volume of Solution)

  17. Procedure • Part A: 1) Tablespoon of baking soda in beaker 2) Mix together 10 mL of vinegar with 5 drops of water 3) Pour the vinegar/water mixture into baking soda 4) Observe and record

  18. Procedure • Part B: • Place a tablespoon of baking soda in beaker 2) Mix together 5 mL of water with 5mL of vinegar 3) Pour the vinegar/water mixture into baking soda 4) Observe and record

  19. Procedure • Part C: 1) Place a tablespoon of baking soda in beaker 2) Mix together 10 mL of water and 5 drops of vinegar 3) Pour the vinegar/water mixture into the baking soda 4) Observe and record

  20. Observations • The reaction that took place was seen like the one shown below

  21. Vinegar vs Water Molarity (mol/L) Time (seconds) Qualitative Observations High Concentration 10 mL vinegar 5 drops of water 0.853 M 15.7 Bubbles Formed Fizzing No baking soda leftover Medium Concentration 5 mL vinegar 5 mL water 0.4375 M 20.95 Less bubbles Less fizzing Some baking soda leftover Low Concentration 5 drops of vinegar 10 mL water 0.0213 M 23.66 Even less bubbles Even less fizzing More baking soda leftover Observations

  22. Sources of error • Time recorded not exact • Hard to see whether reaction complete • Impurities could have resulted in differences in reaction

  23. How concentration affects rate of reaction • Higher concentration = more particles of reactants available • More particles = higher frequency • Higher frequency = faster rate of reaction • Concentration is in direct relation to Rate of reaction

  24. Concentration affecting rate of reaction Simulation of Concentration affecting the rate of reaction: http://www.animatedscience.com.au/learningmodules/collision.swf

  25. Modifications to Experiment • Run all three tests at the same time • Allows for better comparison • More trials • If more tests were conducted = accurate trend

  26. Conclusion • Concentration in direct relation to Rate of reaction • Higher concentration allows more collisions • Lower concentration limits collisions

  27. Application of Concentration • Cleaning detergents • Concentrated soluble soaps such as laundry soaps

  28. CATALYSTS

  29. Experiment: Catalyst Define Catalyst: changes the minimum energy needed for a reaction to occur is not consumed by the reaction

  30. Catalyst in Our Experiment Decomposition of Hydrogen Peroxide 2 H2O2 (aq) + MgO2 (s) → O2(g) + 2 H2O(l) + MgO2 (s) Hydrogen peroxide Manganese dioxide

  31. Procedure Part A Hydrogen Peroxide in test tube Place balloon on top Part B Hydrogen Peroxide and Manganese Dioxide in test tube Place balloon on top

  32. Observations

  33. Error and Modifications Oxygen gas could have escaped Contaminants Measure exact quantities used Measure size of inflation (diameter)

  34. Conclusion By itself, the decomposition of hydrogen peroxide into water and oxygen is slow Manganese dioxide allows this decomposition to take place rapidly The oxygen produced inflated the balloon on the test tube 2 H2O2 (aq) + MgO2 (s) → O2(g) + 2 H2O(l) + MgO2 (s)

  35. Chemical Industry: -more $$ if they make products faster Ex. -Manufacturers of Nitric Acid use catalyst: Platinum -Very expensive metal, but only need small quantity which can be reused Estimate: -90% all commercially produced chemical products involve catalysts at some stage Other: -Energy Processing -Bulk/Fine Chemicals -Food Processing Applications of Catalysts

  36. Rate of Reaction: Overall Conclusion • It was shown form the three experiments that temperature, concentration and the presence of catalysts, affect the rate of reaction Concentration and Temperature -the higher the concentration or temperature, the faster the reaction takes place Catalysts -the presence of positive catalysts, such as Manganese Dioxide, speeds the rate ofreaction

  37. Further research Conduct more experiments -Surface Area -Pressure -Negative catalysts -other factors

  38. Questions?

  39. No Questions. Perfect. Now we have some questions for you.

  40. What is the definition of a reaction?

  41. Summarize the temperature experiment.

  42. What is the reason behind the rate of reaction changing with Temperature and Concentration?

  43. What is a catalyst ?

  44. What was the catalyst used in the decomposition of hydrogen peroxide ?

  45. Name 3 other factors that affect the rate of reaction.

  46. This now concludes our Presentation By: Adrian, Emma, Fraser and Roderick

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