(Originais Teachy 2023) - Question Medium of Chemistry

A chemical equation is a mathematical equation that represents an equality: all atoms and their quantities that appear in the reactants must also be present in the products. Considering a chemical equation and its corresponding equilibrium constant, it can be correctly stated that, by multiplying all its coefficients by 2, the equilibrium constant associated with this new equation will be

It is known that acetone is a type of ketone widely used as a solvent in the industry, mainly for the production of plastics, paints, and varnishes. Furthermore, studies show that its use can pose risks to human health and the environment. Considering the context, answer: a) Describe the general structure of a ketone and what sets it apart from other functional groups. b) Identify and explain some of the risks associated with exposure to acetone for health and the environment. c) Propose individual and collective measures that can be adopted to reduce the negative impacts caused by the responsible use and disposal of acetone.

A chemical laboratory received a sample of a new metallic oxide, and the scientists must determine the chemical formula of the compound based on its properties. The sample reacts with water, forming an acid that, when analyzed, reveals the presence of hydrogen and a metal that behaves as a divalent metal in its reactions. Additionally, the sample reacts with diluted hydrochloric acid, forming a metal chloride and water. If the mass of the metal present in the sample is 27g, determine the chemical formula of the metallic oxide and explain the reasoning used, including the nomenclature of the compounds found.

The German chemist Friedrich August Kekulé was very important for the development of organic chemistry by presenting his postulates on the structure of organic compounds in the 19th century. One of his most important postulates is the tetravalence of carbon. Considering the concept of tetravalence and covalent bonds in organic molecules, answer the following questions: a) Explain why carbon is tetravalent, and briefly describe the relationship of this concept with covalent bonds. b) Give examples of three organic compounds that have tetravalent carbon and their respective structural formulas. c) Describe how the postulate of carbon tetravalence was fundamental for understanding the structures of organic compounds in Kekulé's time and, consequently, how it influenced organic chemistry in general.