1. Determine the Reaction Order for HCl using calculations described in the background section. Show your work. Note that your answer will probably not be a whole number as it is in the examples, so round to the nearest whole number. 2. Determine the Reaction Order for Na2S2O3 using calculations described in the Background section. Show your work. Note that your answer will probably not be a whole number as it is in the examples. 3. Write the rate law for the reaction between HCl and Na2S2O3.

Pre-Lab Preparation 1. Read about chemical reaction rates and rate laws. Take notes on how stoichiometry affects rate (for instance, if 2A + B → C, how do the reaction rates for A and B compare?), what a rate law is, and the three most common rate orders. 2. For the reaction below (the one you will be studying during this lab), write an expression for the reaction rate in terms of changing concentration over time for each species in the overall reaction (one is given as an example). S20g (aq) + 31 (aq) = 2S0, (aq) +l3 (aq) -A[S,0,) rate = Atime I- a. What does it mean if a concentration change over time is written as being negative? b. What does it mean if a concentration change over time is written as being positive? 3. What does activation energy refer to? There are two equations which may be used to calculate this, one with an exponent and a linear form of the same equation. Write down both. 4. What does collision frequency refer to?

9. Write a generic rate law for each line in the graph below and give the appropriate units of k for the graphs below. Rate Mos-1 (2) (3) [A] 10. Convert the integrated rate law for a 1st-order reaction to the slope-intercept form and draw a general graph making sure to identify the y-intercept, slope, x-intercept (with appropriate labels), and label the y- and x-axes with the appropriate labels.

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