Percent Composition Lab Introduction
The percentage of something is very important in everyday life. For example, a farmer would want to know the percentage of nutrients in a fertilizer they are using. In spring, the farmer may want to use a fertilizer that has a high percentage of nitrogen, because it "greens” plants. In the fall, the farmer may want to use a fertilizer that has a higher percentage of potassium, because it strengthens the root systems of plants. A way to find the percentage of nutrients is by using percent composition.
Percent composition is the percent of the total mass of a compound that an element takes up (Texas A&M University, "Chemistry"). To calculate the percent composition of element of a compound, the molar mass of the compound must be found by adding up the masses of each atom in the compound (Texas A&M University, "Chemistry"). This can be done by using a periodic table. Then the mass of the element must be calculated by adding up the mass of its atoms (Texas A&M University, "Chemistry"). Then the mass of the element must be divided by the total molar mass of the compound and then be multiplied by 100 (Texas A&M University, "Chemistry"). For example, the percent composition of sodium (Na) and chlorine (Cl) in sodium chloride (NaCl) are 39.34% and 60.66%. These were found by calculating the molar mass of NaCl, which would be 22.99g/mol of sodium (Na), plus 35.45g/mol of chloride (Cl), which equals 58.44g/mol of NaCl. The total mass of sodium (Na), 22.99g/mol, was then divided by the molar mass of sodium chloride (NaCl), 58.44g/mol and then multiplied by 100, equaling a percent composition of about 39.34% of sodium (Na) in sodium chloride (NaCl). The total mass of chloride (Cl), 35.45g/mol, was then div...
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...ntahydrate is (CuSO 4 ) 5(H 2 O). The molecular formula of copper (II) sulfate pentahydrate is also (CuSO 4 ) 5(H 2 O).
Works Cited
Bailey, Dr. Kristy M. "Stoichiometry Tutorial Finding Molar Mass". Oklahoma City Community College. Web. March 17, 2014.
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2. Cooper, M. M., Cooperative Chemistry Laboratory Manual, McGraw-Hill: New York, NY, 2009, p. 60.
Kim, Taewoo, Trey L Arnold, Kyle A Leland, Aimee M Morey, Department of Chemistry, USAF Academy, CO 80840
Physical Chemistry Laboratory Manual, Physical Chemistry Laboratory, Department of Chemistry, University of Kentucky, Spring 2006.
Number of moles of maleic anhydride = 0.3g ma* (1 mol ma)/(98.016g ma) = 0.00306mol ma
The purpose of this lab was to calculate the percent composition by mass of oxygen in potassium chlorate.
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This chemistry book report is focus on a book called “Napoleon's buttons: How 17 molecules changed history” by Penny Le Couteur and Jay Burreson. The publisher of this book is Tarcher Putnam, the book was published in Canada on 2003 with 17 chapters (hey the number match the title of the book!) and a total of 378 pages. The genre of this book is nonfiction. “Napoleon's Buttons” contain a fascinating story of seventeen groups of molecules that have greatly changed the course of history and continuing affect the world we live in today. It also reveal the astonishing chemical connection among some unrelated events, for example: Chemistry caused New Amsterdamers to be renamed New Yorkers and one little accident of detonating cotton apron in a minor housekeeping mishap lead to the development of modern explosives and the founding of the movie industry.
We thank the University of Oklahoma and the chemistry faculty for providing the space, instructions, and equipment for the development of this report and experiment.
23. S. Alwarappan, S. Boyapalle, A. Kumar, C.-Z. Li and S. Mohapatra, J. Phys. Chem. C, 2012, 116, 6556–6559
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Ionic compounds, when in the solid state, can be described as ionic lattices whose shapes are dictated by the need to place oppositely charged ions close to each other and similarly charged ions as far apart as possible. Though there is some structural diversity in ionic compounds, covalent compounds present us with a world of structural possibilities. From simple linear molecules like H2 to complex chains of atoms like butane (CH3CH2CH2CH3), covalent molecules can take on many shapes. To help decide which shape a polyatomic molecule might prefer we will use Valence Shell Electron Pair Repulsion theory (VSEPR). VSEPR states that electrons like to stay as far away from one another as possible to provide the lowest energy (i.e. most stable) structure for any bonding arrangement. In this way, VSEPR is a powerful tool for predicting the geometries of covalent molecules.
V. Amarnath, D. C. Anthony, K. Amarnath, W. M. Valentine, L. A. Wetterau, D. G. J. Org. Chem. 1991, 56, p. 6924-6931.