Lab Report : Lab # 2
T.A: Thushara Samarasinghe
Chem 184 Spring 2013, Section : 315
When a kernel of popcorn is heated, pressure builds and, depending on the percent of water in the kernel, the kernel pops open and popcorn is produced. The percentage of water in each kernel differs between brands of popcorn. If the steam produced fails to pop the kernel, the kernel becomes hard and burns. The purpose of Part 1, “Popcorn Composition”, of the “Composition and Separations Lab was to determine whether premium popcorn brands display desirable qualities when measured and compared with cheaper brands of popcorn.
The experimental relevance of Part 1 of the experiment was to demonstrate the effects of water in a popcorn kernel when heated and converted to heat. Differences in water percentage determine whether or not the kernel will burst and create popcorn.
In Part 2, “Separating a Solid Mixture”, the purpose was to work with supplies in the lab to separate a solid mixture of popcorn, sand, salt and iron filings into the four separate components to eventually learn the percent composition of the solid mixture. By developing a plan to separate the mixture, the group should have ended up with four separate items with weights that added up to the original weight of the mixture.
The experimental relevance of Part 2 of the experiment was to learn how to separate each component in a four part solid mixture from each other.
In part 1 of this week’s lab three popcorn kernels of a one brand were given to each group. A Bunsen burner was set up by each group and the three kernels were each weighed separately on an electric balance. The Bunsen burner was then lit following the instructions given. (ch185) A 100mL beaker was obtained and filled with a half inch of clean sand. The beaker was placed on a ring stand and one kernel of popcorn was submerged into the sand. The
References: Ch185. How to Light and Adjust a Bunsen Burner. http://ch185.semo.edu/labsafe/bunsen.html (accessed Feb 12, 2013). Composition and Separations. http://linus.chem.ku.edu/genchemlab/184SP13/Download184_Labs/Composition%20and%20Separations%20Chem%20184%20Spring%202013.pdf (accessed Feb 12, 2013) Guidelines for Laboratory Reports http://linus.chem.ku.edu/GenChemLab/184SP13/guidelines%20for%20lab%20reports.htm (accessed Feb 12, 2013)