(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.

Imagine that our body is like a very large city, and the blood needs to reach all parts of this city to deliver oxygen and nutrients. The circulatory system is like the road network of this city, with the heart being the central pumping station and the veins and arteries being the avenues and streets through which the blood travels. Based on what you have learned about the circulatory system, explain how the heart, veins, and arteries work together to circulate blood through the body and mention at least one important function of each of these components.

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.

You must have noticed that the materials we use in our daily lives can change when placed in different situations. For example, water can change its form when heated to make tea, or what happens to fruit when left out of the refrigerator for too long. Think of a material you know and explain how it could change if placed in four different situations: (1) exposed to strong sunlight, (2) placed in the freezer, (3) mixed with another material that reacts with it, and (4) cut into very small pieces. Write about the changes this material could undergo and what causes this change, explaining what happens at the particle level of the materials.