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<div class="moz-cite-prefix">The rate is based off of the
disappearance of peroxide which is tied to the disappearance of
thiosulfate by stoichiometry. The color change took place because
all of the thiosulfate was consumed. Therefore the rate of loss
of peroxide is the rate of loss of thiosulfate divided by 2.</div>
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<div class="moz-cite-prefix">The initial concentration of I- affects
the rate, but when we measure the rate it is always based on the
disappearance of peroxide as described above. If you look at my
spreadsheet, all of the rates<i> (for both the peroxide and iodide
trials)</i> are calculated based on the disappearance of
<math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mstyle
mathvariant="normal"><mo stretchy="false">[</mo><msub><mi>S</mi><mn>2</mn></msub><msubsup><mi>O</mi><mn>3</mn><mrow><mn>2</mn><mo>−</mo></mrow></msubsup><mo
stretchy="false">]</mo></mstyle><annotation encoding="TeX">\mathrm{[S_2O_3^{2-}]}</annotation></semantics></math>
because that is what caused the color change.<br>
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<div class="moz-cite-prefix">Let me know if you have other
questions.<br>
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<div class="moz-cite-prefix">On 2/19/21 9:45 PM, wrote:<br>
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cite="mid:596b49c77f29439883a7423e8f319eec@SA1PR01MB6528.prod.exchangelabs.com">
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Dr. Pounds, this is from CHM 112. I had a quick question for
the Kinetics Concentration Effect Lab Report! When calculating
the rates for the I- Effect, the way to set it up is
(-1/2)(final concentration - initial concentration/ change in
time), correct? I just want to be certain that I am calculating
it correctly!</div>
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Thank you</div>
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<pre class="moz-signature" cols="72">--
Andrew J. Pounds, Ph.D. (<a class="moz-txt-link-abbreviated" href="mailto:pounds_aj@mercer.edu">pounds_aj@mercer.edu</a>)
Professor of Chemistry and Computer Science
Director of the Computational Science Program
Mercer University, Macon, GA 31207 (478) 301-5627
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