Here are
some examples of good observations from Experiment III:
- Water in the
atmosphere can affect the weight of the crucible and salt when we
take it out of the dessicator to weigh it.
- Today is a
pretty damp day. The humidity might make our measurements
heavier!
- The drying
agent in the dessicator could be saturated---the dessicator may
not be completely dry.
- Although we
used the watch glass on top of the beaker to reflux, a lot of
volume escaped through the spout of the beaker anyway.
- When we added
BaCl2, a cloudy white precipitate formed. At the same
time, we saw vapors escaping from the beaker.
- When we
boiled the solution again, the white precipate disappeared. It
redissolved.
- When we
cooled it the redissolved solution to room temperature, the white
precipitate reappeared.
- When we put
it into the ice bath, more precipitate formed and settled to the
bottom.
- I may not
have been able to get all of the precipitate out of the beaker
during filtration.
- Because the
precipitate is soluble in water and we washed it through the
filter with water, the filtrate may contain some of our
weight!!
- The salt was
a large crystalline precipitate before we dried it. After drying,
it looked powdery like baking soda.