Chem Class- October 13, 2009

Today we did a lab on hydrates. We weighed our empty test tube, then our teacher put a hydrate inside. We then used our bunsen burner to evaporate all the water out of the hydrate. It went from a fushia, to a light blue. About 45% of the water in the hydrate evaporated, which was the accepted value. Finally, we calculated our percent error (measured-accepted/accepted). The purpose of the experiment was to determine the empiracle formula of a hydrate.

When it comes to lab safety, we need to be aware that we are using a bunsen burner. This means that long hair should be tied and sleeves should be rolled up so that it doesn't catch on fire. We are also dealing with glassware so it needs to be handled with care and broken glassware should not be used. In addition, we are  electrical equipment is being used (electrical scale) and so it should not be unplugged by pulling on the chord. Finally, we should also wear safetly goggles and a lab apron.

For our lab, the mass of the hydrate (calculate by subtracting the mass of the test tube) was 1.0 g. The mass after heating was 0.6 g which meant that 0.4g of water was realsed during the heating and 40% of the hydrate waswater. Our percent error was 11.1%.

We also have our test coming up for this unit.
60% of the test will be mainly naming chemicals (Chemical Nomenclature):

• Ionic
• Polyatomic
• Multivalent (IUPAC and Classical-Latin)
• Molecular
• Acids/Bases
• Hydrates
• Ions

The other portion of the exam will consist of the classification of matter (Heterogeneous and Homogeneous substances) and separating mixtures (Chromatography, Crystalization, Distillation, Filtration, by hand...)