Imagine that you are climbing a mountain.
(a) Is the distance you travel to the top a state function?
(b) Is the change in elevation between your base camp and the peak a state function? [Section 5.2]
CH 111 Notes: Week 4 Combustion Reactions: an organic substance combines with oxygen and is burned, giving off heat energy and creating carbon dioxide and water o Propane (C H 3 8 C 3 +85O → 32CO + 4H O2 2 Empirical Formula: the formula of a molecule with the smallest whole number ratio of atoms o C 5 4 vs. C10 8 → related by a whole number multiple of 2 In a combustion reaction, 135.0 mg of a hydrocarbon reacts with excess oxygen to produce 440.0 mg of carbon dioxide and 135.0 mg water. The hydrocarbon MM = 270 g/mol. Determine the empirical and molecular formulas. o C x +yO → C2 + H O 2 2 -3 0.4400 g CO (1 2ol CO /44.012g)(1 mol C/1 mol CO ) = 9.9977x12 mol C -2 0.1350 g H O 2 1 mol H O/18.22 g)(2 mol H/1 mol H O) = 1.4983210 mol H X = 9.9977x10 mol C/9.9977x10 mol C = 1 (x2) = 2 -2 -3 *Divide C and H by the lower number of Y = 1.4983x10 mol H /9.9977x10 mol C = 1.499 (x2) = 3 Empirical Formula: C H 2 3 moles and multiply to get to the nearest whole number MM C H 2 37.05 g/mol (270 g/mol)/(27.05 g/mol) = 10 C 2
