Another fun-packed Sunday learning chemistry for our class. The day began with a brief review and quiz covering temperature conversions, accuracy vs. precision, and drawing a laboratory set-up. After the quiz we discussed the states of matter and the classification of matter. We then separated a heterogeneous mixture of salt and sand. This gave students an opportunity to apply what they had learned about recording observations. Some lessons learned included how to handle hot glassware and the difference between beakers and erlenmeyer flasks when it comes to removing a solid product from the bottom of a vessel.
Our next topic was a discussion of density. We didn’t have much time for working through the many problems possible with the density equation.
It is important to understand how to rearrange the d=m/V equation to also solve for mass (m=d*V) or volume (V=m/d). The best way to learn how to work these problems is to do lots of them. The drill sheet provides some practice but I also suggest: this online density worksheet. Embedded in some density problems is the concept of mass by difference (subtracting out an empty container) and volume by difference (displacement of water, the water level rises when a solid object is submerged).
Our last activity was to explore the properties of an emulsion. Listen to the podcast on Molecular Gastronomy to hear a description of this tasty activity. Students exchanged business cards that they made themselves representing the elements.
Cards included slogans such as “I put the C L in clean”, for chlorine. The cards were a lot of fun and hopefully will become flash cards to help students learn the symbols and names of the elements. We ended the day with a discussion of a couple of wonderful books about the elements: The Elements and Nature’s Building Blocks. It is important to remember the seven diatomic molecules: H2, N2, O2, F2, Cl2, Br2, and I2, and also the two unusual elemental forms for phosphorus (P4) and sulfur (S8).
There will be a quiz next week (density, classification of matter, states of matter, names and symbols of the elements, counting atoms in chemical formulas) and the first Exam will occur on February 28th. Homework should be completed through Chapter Three by next week. Laboratory notebooks will be collected on the day of the exam. Next week we will only carry out one laboratory: Identification of an Unknown solid.