In
order to have clean glassware for lab work, someone needs to go through
many steps of washing the flasks and beakers.
Here is
Amy, ready to start this work!
Here is
the "recipe" for clean glassware:
 Wash
the glassware with Alconox, a biodegradable detergent soap.
 Rinse
with tap water.
 Soak
the glassware in a basic Contrad solution of potassium hydroxide for
four hours.
 Rinse
with tap water at least six times.
 Do an
"acid rinse" by using hydrochloric acid to rinse the glassware
inside and out.
 Rinse
with deionized water.
 Rinse
again with hydrochloric acid inside and out.
 Rinse
with deionized water 6 more times.
 Bake
for four hours in a Muffle furnace at 550C° , the maximum temperature
for this glassware.
 When
the glassware has cooled to 100150° C, cover the tops with aluminum
foil caps that have been "cooked" for four hours.
OK,
how long will it take Amy to do a "load" of glassware?
Amy is
a fast worker, but it still takes her 1.5 minutes to wash or rinse the
small flask, 2 minutes to wash or rinse the mediumsized flask, and
2.5 minutes to wash or rinse the large flask.
Here
are the flasks she has to wash:
As you
can see, there are 3 large flasks, 3 mediumsized flasks, and 3 small
ones.
So, how
long will it take her to clean this amount of glassware, from beginning
with the detergent wash to removing the glassware from the oven (steps
19 above)?
There
are many ways to solve this problem. Here are some hints:
You might
want to count the number of times each flask has to be washed or rinsed.
Each one is washed or rinsed separately.
You will
need to add in the soaking time and the time the flasks spend in the
oven. All the flasks will fit into the oven at the same time.
Work with
someone else to talk about ways in which to solve this problem!
Here
is Amy, when her work is done!
Michele
takes the clean glassware out of the oven. The glassware is ready to
be used again!
