I voted to close.
Mathematics can be used in many other areas. However, the field of applied mathematics is different from the collection of all applications of mathematics.
When you can't figure out what is going on in a chemical system, sometimes the problem is with your understanding of the relevant chemistry instead of the analysis of a mathematical model. If the problem is that we don't understand the physical chemistry, say the phenomenon of supercooling, or the effects of dissolved gases, then this is not an applied math problem, and we can't expect mathematicians to help. We need to ask chemists who study these things. Scientists generally know the basics of mathematical modeling, perhaps better than most mathematicians, so basic modeling issues are not a stumbling block. If the chemical phenomena are understood, but the mathematical model is too unreliable or slow, or we want a general explanation of the results, then it is an applied mathematics problem.
The original question was off-topic because it did not make the question an applied math problem. The competition on the Mpemba effect was run by the Royal Society of Chemists. The arXive paper cited was in the chemical physics section of the arXive and had no mathematics classifier. (I'm skeptical of it, but I can't judge it because I'm not a chemist.) The explanations of the Mpemba effect that I have heard depend on diverse and complicated physical and chemical phenomena. Why was this question asked on MathOverflow instead of chemistry.stackexchange.com or physics.stackexchange.com?
I'm quite skeptical of the suggestion that it's not possible to separate the phenomena experimentally. AFAIK, that's a significant portion of what experimental scientists do. Which separations are possible by clever experimental design, e.g., whether we can control or eliminate convection, is not a mathematical issue.
I welcome actual questions on applied mathematics, and I have argued many times in the past that pure mathematicians have incorrectly closed questions on applied mathematics, that pure mathematicians should welcome the presence of applied mathematics on MathOverflow. The original question just doesn't look like a question on applied mathematics. Perhaps the edit helped, but I don't think it did enough.