Notes: 1. Carry out the procedure at three separate temperatures at least 15 deg

Question

Notes: 1. Carry out the procedure at three separate temperatures at least 15 degrees apart 2. Use the Rate Law of Rate k-](H202] 3. Using Excel Plot Ink' (Y-axis) Vs 1/T (x-axis). The Slope of the Graph- Ea/R and R 8.314J/(mol/k) 4. Enter your collected data below, The columns that are highlighted red you must calculate using formulas in excels and linking to other cells when appropriate. (See Example Tab Below) Determination of the Activation Energy Trial Cold Temperature Medium Temperature 43 50 High Temperature Time (s) Reaction Rate Calc. k In(k) Temp (C) Temp (K)1/Temp(K) Plot Graph--> Activation Energy (Ea) (J/Mole) Value of -Ea/R Activation Energy (Ea) (KJ/Mole) Post Lab Questions 1. Accounting for the change in concentration due to dilution is a critical aspect of this experiment. Calculate the concentration of the I- ions in a solution if 6.0 mL of 0.30 M KI is added to 4.0 mL of 0.45 M Nal and 2.0 mL of water.

Explanation / Answer

The rate determining step is important in deriving the rate equation of a chemical reaction. For example, consider a multi-step reaction:

A+BC+DA+BC+D

Assume the elementary steps for this reaction are the following:

Step 1: Slow    A+AC+EA+AC+E   (with a rate constant, k1k1)

Step 2: Fast    E+BA+DE+BA+D   (with a rate constant, k2k2)

where E is an intermediate, the product in step 1 and a reactant in step 2 that does not show up in the overall reaction. This is because when steps 1 and 2 are added, intermediate E cancels out, along with the extra reactant A from step 1. Note that intermediate reactions do not show up in the overall reaction.

In the case of this hypothetical reaction, if step 1 is the slow step and step 2 is the fast step of the reaction, then the overall reaction rate depends on step 1; the slow step in a reaction is always the rate-limiting step, another name for the rate determining step.

Therefore the rate equation is,

rate=k1[A][A]=k1[A]2

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