(Originais Teachy 2023) - Question Easy of Sciences

In the solutions used in laboratories, the concentrations of ions $$\mathrm{H}_{3} \mathrm{O}^{+}$$ are usually small and a simple way to express the hydrogenionic concentration of a solution is through pH. Solutions of weak acids and bases present, in solution, an equilibrium between the various particles and, in this case, we have the equilibrium constant, that is, the ionization constant. A solution of $$1.10^{-3} \mathrm{mol}^{-1}$$ of bromoacetic acid $$\left(\mathrm{BrCH}_{2} \mathrm{CO}_{2} \mathrm{H}\right)$$ has an ionization constant equal to $$6.3.10^{-5} \mathrm{e}$$ and a solution of $$1.10^{-3} \mathrm{mol}^{-1}$$ of 4-chlorobenzoic acid $$\left(\mathrm{ClC}_{6} \mathrm{H}_{4} \mathrm{CO}_{2} \mathrm{H}\right)$$ has an ionization constant of $$1.0.10^{-4}$$. Given the following statements, I. 4-chlorobenzoic acid has a higher $$\mathrm{pH}$$ than bromoacetic acid. II. Bromoacetic acid is weaker than 4-chlorobenzoic acid. III. Since the concentrations are equal, both acids have the same $$\mathrm{pH}$$. IV. Bromoacetic acid has a higher $$\mathrm{pH}$$ than 4-chlorobenzoic acid. v. 4-chlorobenzoic acid is weaker than bromoacetic acid. It is verified that only ii and iv are correct.

What are the problems caused by the standardization of crops?

The evolution of the Solar System is a complex process that involves the formation of stars, planets, and other celestial bodies from a large cloud of gas and dust. Studying this evolution not only expands our knowledge of the cosmos but also allows us to understand fundamental aspects of physics and chemistry. On the other hand, ancient cultures developed mythologies and interpretations about the origin and evolution of celestial bodies, often based on astronomical observations and their own traditions. Considering the historical and scientific context, describe the evolution of the Solar System from its beginning in a molecular cloud to the formation and stabilization of planets. Explain how the observations and interpretations of ancient cultures can be related to this evolutionary process, even though they did not have the scientific knowledge we have today.

When the leaves fall from the trees, they begin to decompose on the forest floor. This decomposition process is very important for nature, as it releases nutrients that were stored in the leaves back into the soil. Fungi and bacteria play a key role in this stage of the life cycle, acting as decomposers. An experiment was conducted in a forest area where leaves from different trees were collected. Each set of leaves was placed in a separate container and kept under suitable conditions to observe decomposition. The experiment lasted several weeks and the students regularly noted the changes that occurred. At the end of the experiment, they compared the decomposition state of each set of leaves. Based on the natural cycle, the importance of decomposition, and the described experiment, what conclusion can be drawn about the role of the fungi and bacteria observed in the decomposition of leaves in the forest?