Chemistry is a magical science. Without any exaggeration, magical, because it studies the transformation of one substance into another. Chemistry is considered to be a complex science, difficult to understand, requiring diligent cramming, although in fact it is not.Chemistry is extremely logical. In it, everything happens in full accordance with the laws. If you know the rules, then you don't need to cram anything. Need to understand. What chemistry does not forgive is knowledge gaps. With the same physics, things are a little different. You can have an excellent understanding of mechanics without knowing optics at all. With chemistry, such a number will not work. Sooner or later, the gap will come around, will make itself felt in a completely unexpected situation. Everything seems to be correct, it seems that in the course of the reaction one substance should have turned out, but another has turned out. As it was sung in one old song: "I wanted to make a thunderstorm, but I got a goat." An exception? Nothing like this! Chemistry practically knows no exceptions, and those that exist are also logical and explainable.