AP Chemistry, 4
The purpose of this experiment was to investigate how the rate of a reaction
can be measured and how reaction conditions affect reaction rates.
We began by obtaining a microtip Beral-type pipet and filling it with 3 mL
of distilled water. We massed a small beaker with a balance, and then used a pipet
to deliver five drops of water into the beaker, and then measured that total mass.
We added an additional five drops of water into the beaker and determined that
mass, and then added another five more drops, determining the mass once more.
To best determine the average mass of one drop of water, we found the average
mass of a drop of water in each of these three trials, and then took the average of
We then took six microtip pipets and filled them with 2 mL each of KI,
O, HCl, starch, Na
, and KBrO
. We then took a well plate, and then
performed seven different experiments, by making a twelve drop mixture with
different quantities of each solution, and then recording the time that it took for
each of the mixtures to react. We were able to determine when a mixture had
reacted when the color changed. We also took the temperature of one of the
reaction solutions and assumed this temperature constant.
Afterwards, we prepared a shallow warm water bath of about 40 °C, and
filled the six wells in our reaction strip with the given number of drops from the
previous experiment. After that we placed our Beral pipet in the bath and filled it
half-full with 0.040 M KBrO
solution. Five minutes later we recorded the
temperature of the water, took the pipet out of the water, and with the reaction
strip still in the bath, added two drops of KBrO3 solution to the first well, stirred,
and started our timer. We recorded the time it took for the first blue color to
appear, and then repeated this process for the other two wells. We then used ice