CHM 2045 Lecture Notes - Lecture 4: Combustion Analysis, Chemical Formula, Ionic Compound

• School: University of Florida
• Department: Chemistry
• Course: CHM 2045
• Professor: Gower Jeff

Document Summary

Example) how many grams of nitrogen are in 15 grams of n2o4: (15 g n2o4)*(1 mol n2o4/92. 02 g n2o4)*(2 mol n/1 mol. N2o4)*(14. 01 g n/1 mol n) = 4. 567 grams n. Example) what is the mass percent of nitrogen in n2o4: mass percent = mass of a part/mass of the whole, (4. 567 g n)/(15. 00 g n2o4)*(100%) = 30. 45% To find mass percent without having to calculate the grams: (mole coefficient n x molar mass of the element) / (molar mass of the compound) * 100% Moles of the element in a compound = n. Assume that there is 1 mole of the compound in order to find the molar mass of that compound: the exact number of atoms of each element in the smallest unit. Empirical formula: shows the simplest whole number ratios of the atoms in a, helps to determine the molecular formula when there is an substance unknown. Empirical formula: ch2o molecular formula: c6h12o6.