<p>I have a friend who double-majored in math and chemistry, so it can definitely be done. However, I highly doubt that these two majors mix or complement each other on the undergraduate level, and mathematical chemistry is a rather obscure field even for graduate school. The Wiki article zapfino linked to refers to the International Academy of Mathematical Chemistry, which has exactly 27 members in the US (~100 worldwide). For comparison, the American Chemical Society has more than 160,000 members.</p>
<p>You said that you are interested in applied mathematics. The fields that currently provide the most opportunities for that are physics, engineering, computer science and economics. </p>
<p>I would encourage you to keep an open mind about the possibility of changing your major later on. I loved gen chem and hated orgo, which marked the end of my chemistry career. Many students switch to a quantitative non-math major when they hit real analysis and abstract algebra (“abstract non-sense”).</p>