We include all forces in the label. In the same way that gravity doesn't stop applying when a magnet picks up a nail, LD doesn't stop applying when DD is introduced: it's just overpowered. *Also, a receiver does nothing without a donor, so only include if it's an HB receiver if there are HB 's in the mixture to receive. Do note that molecules can donate and receive HB from copies of itself: so if it has HB+ regions, it is also likely to have HB - regions. You can quickly memorize these 4 labels. Around 15-20\% of your grade in CHM124 and 126 comes from IMF labeling. It will serve you to learn it quickly. IMF Step-by-Step Guide 1) Identify all of the electronegative atoms ( N&O ), use a star if it helps 2) Identify all of the atoms that are being "pulled on" by their electronegativity, use a cross if it helps. Then circle those atoms and label them polar (P). You can extend a circle to include multiple regions if they have the same forces