Cliffs AP Chemistry, 3rd Edition

Part IV. Reaction Order with Respect to Iodide Ion

Beaker A Beaker B

0.05 MKI [I–] 0.05 M Na 2 S 2 O 3 Buffer1 0.1 M H 2 O 2 [H 2 O 2 ] Time Initial rate

(mL) (M) (mL) (mL) (mL) (M) (sec) (M/s)

10.0 0.0100 1.0 19.0 20.0 0.040 35 1.42857 × 10 –5

8.0 0.0080 1.0 21.0 20.0 0.040 52 9.61538 × 10 –6

6.0 0.0060 1.0 23.0 20.0 0.040 62 8.06452 × 10 –6

4.0 0.0040 1.0 25.0 20.0 0.040 71 7.04225 × 10 –6

3.0 0.0030 1.0 26.0 20.0 0.040 140 3.57143 × 10 –6

Partial order with respect to iodide ion = First order according to Graph for Part 4

Y = 1st order = 0.9789 *slope = order = y

[I–] log [I–] time (sec) rate log rate

0.01 − 2 35 1.42857 × 10 −^05 −4.84509804

0.008 −2.096910013 52 9.61538 × 10 −^06 −5.017033339

0.006 −2.22184875 62 8.06452 × 10 −^06 −5.093421685

0.004 −2.397940009 71 7.04225 × 10 −^06 −5.152288344

0.003 −2.5228 78745 140 3.57143 × 10 −^06 −5.447158031

Part V. Overall Reaction Order and the Rate Constant

Overall reaction order: Second Order

Average experimental rate constant 7.1467 × 10 –4

Graph for Part 4

log [I-]

log rate y = 0.9789x − 2.9105

log rate

linear (log rate)

-3 -2.5 -2 -1.5 -1 -0.5 0

-4.8

-5

-5.2

-5.4

-5.6

Part III: AP Chemistry Laboratory Experiments