Nursing Entrance Exam

Chemistry (IUPAC). Elements listed on the table under 113, 115, 117, and 118 have been synthesized, but are yet to officially be recognized by the IUPAC; they are only known by their systematic element names. 9.2.6 Chemical Reactions Chemistry is the science and study of matter, particularly its chemical reactions; however, chemistry also includes the composition, structure, and properties of chemicals and reactions. Chemistry deals with atoms and their interactions with other atoms, particularly with the properties of chemical bonds. Chemistry is often referred to as “the central science,” as it connects the natural sciences, such as geology and biology, with other natural sciences. Chemistry is a branch of physical science that is distinct from physics. Traditional chemistry starts with the study of elementary particles, atoms, molecules, substances, metals, crystals, and other aggregates of matter, including solid, liquid, and gas states, whether in isolation or combination. The interactions, reactions, and transformations that are studied in chemistry are a result of interactions either between different chemical substances or between matter and energy. A chemical reaction is a transformation of some substances into one or more different substances. A chemical equation is a method for symbolically depicting a chemical reaction. Oftentimes, in a chemical transformation equation, the number of atoms on the left and the right are equal. The nature of chemical reactions a substance undergoes and the accompanying energy changes are constrained by certain basic rules, also called chemical laws. In nearly all chemical studies, energy and entropy considerations are undoubtedly important. In addition to being classified based on structure and phase, chemical substances are also categorized according to their chemical compositions. They can be analyzed using the tools of chemical analyses – spectroscopy and chromatography. Compound A compound is a substance with a particular ratio of atoms of certain chemical elements that determine its composition with a particular organization that determines its chemical properties. For instance, water is a compound that contains the elements hydrogen and oxygen in a 2:1 ratio, with the oxygen atom between the two hydrogen atoms, and an angle of 104.5° between them. Chemical reactions are responsible for forming and interconverting compounds.

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