Tasks for classification of simple and complex substances take place to be aware not only chemistry, but also in the school program in natural study. In addition, children even of younger school age which it is necessary to give the answer, available to their perception, can sometimes ask such questions.
Instruction
1. Substance is what the physical body consists of. That is, for example, chalk consists of limestone, the Golden Ring has gold in structure, and the nail is made of metal – iron. All substances are divided into difficult and simple which are rather easy for classifying by a chemical formula.
2. Each connection has own formula which consists of chemical symbols and indexes. Indexes show number of atoms of this element which is a part of simple or difficult connection. Some substances consist of one type of atoms and Na sodium, sulfur S, Si silicon have no indexes, for example. Other substances – opposite, consist of several different elements, and their number defined by indexes can be various. For example, CaSO3 calcium carbonate, nitrate of Cu(NO3) 2 copper, sulfate of Al2(SO4) 3 aluminum.
3. To distinguish what substance – simple or difficult, it is necessary to analyze its chemical formula. If it consists only of one type of atoms of any chemical element, then this simple substance. The amount of atoms can be various. For example, the substances which are consisting of one type of chemical element and having one atom (indexes are absent) is a lithium of Li, Na sodium, Ca calcium, Fe iron, Mn manganese. To the connections incorporating one type of chemical element, but several its atoms (on the right there is an index showing this number), it is possible to carry N2 nitrogen, O2 oxygen, O3 ozone, H2 hydrogen, Cl2 chlorine.
4. Substances which consist of several types of chemical elements are called difficult. And some connections have no indexes, for example at such as, bromovodorodny HBr acid, sodium chloride (table salt) of NaCl, BaO barium oxide. Other difficult connections have different indexes. It is possible to carry to them: HNO3 nitric acid, hydroxide of Cu(OН) 2 copper, ortho-phosphate of K3PO4 potassium and the vast majority of substances in the nature.