中文
HOME
HOME / LATEST NEWS / Content

Chemistry Group: Modern Techniques in High School Chemistry Teaching

October 23, 2017

Chemistry Group: Modern Techniques in High School Chemistry Teaching

Recently, the chemistry group organized a learning and discussion workshop about the “applications of modern analytical techniques in High School Chemistry teaching” in the Modern Analytical Chemistry Laboratory in the Yifu building. Mr. Sun Hao introduced some of the IB students’ research work at the beginning of the workshop, to demonstrate how modern analytical instruments can be used in the classroom. In the lab students can make use of draught cupboards, cold water showers, electronic balances, infrared spectrophotometers, ultraviolet spectrophotometers, atomic absorption spectroscopy equipment, gas chromatographs, GC-MS, and so on. After Mr. Sun Hao described some experiments performed on such instruments, the teachers tried out the instruments for themselves.

The first instrument they tried out was the infrared spectrophotometer. Infrared spectrophotometers make use of potassium bromide, which is a deliquescent compound that is hygroscopic and becomes wet when exposed to moist air. Therefore it is important to keep the lab and agents dry before testing. Before the teachers performed the test, all the samples were dried out. The teachers first cleaned all the tools with alcohol and milled 200mg of potassium bromide with the sample. When tableting the sample with KBr, gas was avoided to make the measurement as precise as possible. A tablet was then tested using an infrared spectrophotometer. Compared with the standard spectrum, the tested sample was benzoic acid. Then the teachers tried out the Ultraviolet Spectrophotometer. Using a pre-prepared standard solution, the teachers measured the sample at a wavelength of 460 nm and compared it with the standard spectrum.

Students have to be familiar with the use of pipettes when they perform such experiments. Before the use of atomic absorption spectroscopy, organic compounds in the sample should be cleaned out in case an incomplete burned sample blocks the narrow and long entrances, which may cause explosion of the machine. Certain lights are used to detect certain elements.

The teachers tested then and compared the quantity of calcium in two kinds of bottled mineral water: Ganten and Nongfu Spring. The calcium content of Ganten is 4.497 mg/L while the calcium content of Nongfu is 8.770 mg/L. At last, the GC-MS was illustrated to separate mixtures of toluene and banana oil. As a closure to the day’s learning workshop, a discussion was had about combining results from different instruments to verify results.

(Written by Sophia Yang Picture by Sophia Yang)