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reactants products

reactants products. Formulate an definition of reaction rate . Identify variables used to monitor reaction rates Examples: pressure, temperature, pH, conductivity Perform calculations to measure average and instantaneous rate .

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reactants products

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  1. reactants products

  2. Formulate an definition of reaction rate. • Identifyvariables used to monitor reaction rates • Examples: pressure, temperature, pH, conductivity • Perform calculations to measure average and instantaneous rate. • Compare rates given experimental rate data and reaction stoichiometry. Additional KEY Terms

  3. Kinetics Branch of chemistry that studies the speed or rate with which chemical reactions occur. Some reactions do not occur in one simple step. Some occur in several more complex steps. Kinetics includes studying the steps, or mechanism, of a chemical reaction.

  4. Rate - refers to the speed of the reaction • How fast reactants are used or productsform. A(s) + B(l) C(g) + heat exothermic A(s) + heat C(g) + B(l) endothermic

  5. Rate can be measured using different methods depending on the reaction: (°C/min) (kPa/s or mmHg/s) (g/min) Colour, pH, conductivity(over time).

  6. A(s) + B(l) C(g) + heat *We will only use concentration change with time.

  7. Average Rate is described as total change in concentration of reactant or product over time. Rate = Δ[A] Δt Rate = [A]final - [A]initial Reactions have quick initial rates, but slow down over time. tfinal - tinitial

  8. Instantaneous rate - rate at a specific time. Determined by calculating the slope of the line tangent to a point on the curve. Concentration Time

  9. A B Calculating Average Rate

  10. a. What is the average rate over the entire 50 seconds?

  11. b. What is the average rate for the interval 20 s to 40 s?

  12. 2 NO2(g) 2 NO (g) + O2(g) Decomposition of nitrogen dioxide produces nitrogen monoxide and oxygen:

  13. a. Ave. rate of decomposition of NO2 over 400 s. Rate is always expressed as a positive value. Actual value is 1.75 x 10-4 mol/L·s

  14. b. Ave. rate of production of O2 over 400 s.

  15. 2 NO2(g) 2 NO (g) + O2(g) Rates can be predicted from reaction stoichiometry.

  16. rate of decomposition of NO2 is equal to the production of NO - molar coefficients are 1:1. 2 NO2(g) 2 NO (g) + O2(g) • rate of production of O2 is half of the NO - • molar coefficients are 1:2. Δ[NO2] Δt = Δ[O2] Δt ½ = Δ[O2] Δt Δ[NO] Δt 2

  17. What is the rate of production of C and the rate of disappearance of B if A is used up at a rate of 0.60 mol/Ls? 2 A + B 3 C 1 mol B 3 mol C 2 mol A 2 mol A 0.60 mol/L·s A = 0.30 mol/L·s B 0.60 mol/L·s A = 0.90 mol/L·s C

  18. CAN YOU / HAVE YOU? • Formulate an definition of reaction rate. • Identifyvariables used to monitor reaction rates • Examples: pressure, temperature, pH, conductivity • Perform calculations to measure average and instantaneous rate. • Compare rates given experimental rate data and reaction stoichiometry.

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