The molecular formula for n-pentane is C5H12. This means that each molecule of n-pentane contains 5 carbon atoms and 12 hydrogen atoms. To calculate the molecular mass, we can use the atomic masses of carbon (approximately 12.01 g/mol) and hydrogen (approximately 1.008 g/mol).
Calculating the molecular mass:
- Mass of Carbon: 5 atoms × 12.01 g/mol = 60.05 g/mol
- Mass of Hydrogen: 12 atoms × 1.008 g/mol = 12.096 g/mol
Adding these together gives:
60.05 g/mol + 12.096 g/mol = 72.146 g/mol
Thus, the molecular mass of n-pentane is approximately 72.15 g/mol.
Next, let’s draw its Lewis structure:
The Lewis structure shows how the carbon atoms bond together in a chain, with hydrogen atoms filling the remaining valences of the carbon atoms. In total, n-pentane has a linear arrangement of carbon atoms, resembling a straight chain.
Finally, the intermolecular forces present in n-pentane include:
- Dispersion Forces: These are weak forces that arise due to temporary shifts in electron density. They are present in all molecules, including nonpolar molecules like n-pentane.
- Dipole-Induced Dipole Forces: While n-pentane is a nonpolar molecule, it can induce a dipole in nearby polar molecules, leading to this type of interaction.
In summary, n-pentane has a molecular formula of C5H12, a molecular mass of approximately 72.15 g/mol, a linear Lewis structure, and experiences dispersion forces and dipole-induced dipole forces.