(Originais Teachy 2023) - Question Medium of Chemistry

The addition reaction is a chemical reaction that occurs between two or more reactants and produces a single product. This reaction is characterized by the addition of a functional group to another, the latter usually being an alkene. Which of the following substances is an alkene?

During a Chemistry class, a 1st-year high school student realized that the concept of mole, essential for understanding chemical reactions, could be applied in a daily life context. He decided to analyze the bread-making process to understand the importance of measuring the amount of reactants, such as yeast, to ensure the quality of the final product. Considering that 1 mole of any substance contains approximately 6.02 x 10^23 elementary entities, and knowing that biological yeast is a mixture of compressed yeast cells and starch, the student proposed the following calculation: 'If a baker uses 25 g of biological yeast to make 3 loaves of bread, and each loaf requires exactly 8 g of yeast for the dough to rise properly, what is the amount of matter, in moles, of biological yeast that the baker uses in each loaf?' Based on this information, answer: 1) What is the relationship between the mass of yeast used per loaf and the molar mass of yeast? 2) What is the practical importance, in terms of bread quality, of measuring the correct amount of yeast matter used in each loaf?

When studying covalent bonds, 1st-year high school students learned about Lewis theory, which describes the formation of covalent bonds through the sharing of electron pairs between atoms. Considering that the covalent bond is formed between two non-metals, propose and explain an example of a covalent compound, highlighting its structural formula and how Lewis theory can be applied to describe the formation of covalent bonds in the chosen compound. Additionally, briefly discuss a characteristic physical or chemical property of this type of covalent compound that differentiates it from ionic or metallic compounds.