سؤال قراءة ستيب محلول — المفردات في السياق (تدريب 5235)

(8) Decomposition of compounds into elements and the combination of elements to make compounds are examples of chemical processes. Using the atomic theory, such processes are seen as changes in the combinations of atoms. Such transformations are called chemical reactions. The term reaction means to produce a result. A chemical reaction is a process in which one set of chemicals is mixed and transformed into a new set of chemicals. When charcoal, which is mostly elemental carbon, burns in air, the process is envisioned as carbon atoms combining with diatomic oxygen molecules to produce molecules of carbon dioxide gas. (9) As mentioned above, the law of conservation of matter expresses that atoms are not created or destroyed in chemical processes. In other words, atoms are conserved in chemical reactions. A reaction is a special process in which certain chemical combinations of atoms transform into new combinations of atoms. In a reaction, the total atom count does not change. Thus, destroying matter by chemical reactions is not possible.