The document provides a table summarizing the modes of different molecules, including argon, HCl, and ethane (C2H6). It calculates the total number of modes by considering translational, rotational, and vibrational contributions. For argon the total is 3, for HCl it is 6 at high temperatures, and for ethane, it is 9.

1. Fill in the table below for the molecules shown. HCI Ar (atom) Ethane, C2Ho # total modes #
translational modes # rotational modes # vibrational modes
Solution
Argon : 3 (translational) + 0(rotational) + 0(vibrational)
= 3(total)
HCl : 3(translational) + 2(rotational) + 1(vibrational - high T)
= 6(total - high T)
C2H6 : 3(translational) + 3(rotational)