Use Table 5.3 to calculate the enthalpy change for the combustion of \(1 \ mol\) of ethanol:
\(\mathrm{C}_2\mathrm{H}_5\mathrm{OH}(l)+3\mathrm{\ O}_2(g)\longrightarrow2\mathrm{\ CO}_2(g)+3\mathrm{\ H}_2\mathrm{O}(l)\)
Equation Transcription:
Text Transcription:
1 mol
C_2 H_5 OH(l) + 3 O_2 (g) rightarrow 2 CO_2 (g) + 3 H_2 O(l)
Chapter 12 Lecture Notes Things to remember o Remember that properties of gases can be related by PV=nRT (ideal gas law) o Remember that molecules of gases are far apart, while molecules in liquid and solid are closely packed o Remember that molecules can have polar bonds, due to differences in electronegativity of bonded atoms o Intramolecular bonds are strong Covalent: 100-400 kJ/mol Ionic: 700 -1100 kJ/mol o Intramolecular forces: forces holding atoms together to form molecules (covalent bonds, ionic bonds) o Intermolecular forces: electrostatic interactions between molecules that are weaker than forces between oppositely charged ions Intermolecular forces o Directly related to melting point, boiling point, and energy needed for phase changes (convert solid to liquid or liquid to vapor) o Important in determining solubility of gases, liquids, and solids in various solvents o Crucial in determining structures of biologically important molecules Ion-ion forces, for comparison of magnitude o Na+ - Cl- in salt The strongest forces Lead to solids with high melting temperatures NaCl = 800 degrees C Types of intermolecular forces o Ion-dipole o Dipole-dipole o Dipole-induced dipole o Induced dipole-induced dipole Attraction between ions and
