(Originais Teachy 2024) - Question Easy of Chemistry

A white solid presents the following properties: I. It is soluble in water. II. Its aqueous solution conducts electric current. III. When pure, the solid does not conduct electric current. IV. When melted, the resulting pure liquid does not conduct electric current. Considering this information, the solid in question can be

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?

Consider that a group of students conducted an experiment in the Chemistry laboratory by mixing 10 grams of salt (sodium chloride) in a cup containing 200 mL of water. After the mixture reached homogeneity, we call this mixture a solution. Calculate the concentration in g/L of this solution and identify which of the alternatives below best describes the relationship between solute, solvent, and concentration in the solution?

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?