Determine the Molecular Formula and Molecular Mass for n-Hexane, Draw its Lewis Structure, and List All Intermolecular Forces Present

The molecular formula for n-hexane is C₆H₁₄. To determine the molecular mass, we need to calculate the total atomic masses of its constituent elements. Carbon (C) has an atomic mass of approximately 12.01 g/mol, and hydrogen (H) has an atomic mass of about 1.008 g/mol. Therefore, the molecular mass can be calculated as follows:

• Carbon: 6 atoms × 12.01 g/mol = 72.06 g/mol
• Hydrogen: 14 atoms × 1.008 g/mol = 14.112 g/mol

Adding these together gives:

72.06 g/mol + 14.112 g/mol = 86.172 g/mol

So, the molecular mass of n-hexane is approximately 86.17 g/mol.

Next, let’s draw the Lewis structure for n-hexane. In the Lewis structure, we arrange the carbon atoms in a straight chain, with hydrogen atoms filling the remaining valences:

  H   H   H   H   H   H
   |   |   |   |   |   |
H–C–C–C–C–C–C–H
   |   |   |   |   |   |
  H   H   H   H   H   H

Each carbon atom forms four bonds (either with hydrogen or other carbon atoms), and each terminal carbon is bonded to three hydrogen atoms while each internal carbon is bonded to two hydrogen atoms.

Now, regarding the intermolecular forces present in n-hexane, we predominantly have van der Waals forces (also known as London dispersion forces). These forces arise due to the temporary dipoles that occur when electrons are unevenly distributed within the molecule. Additionally, there might be very weak dipole-induced dipole interactions, given that n-hexane is a non-polar molecule and the interactions are relatively minimal compared to polar molecules. However, no hydrogen bonding or dipole-dipole interactions are present due to the lack of polar functional groups in n-hexane.