(Originais Teachy 2023) - Question Medium 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.

Using electrical energy efficiently is a way to save natural resources, as it is possible to use devices that consume less energy. What is the main way to take advantage of electrical energy efficiently?

Plants are very special living beings! They need water and sunlight to grow, just like we need food and water to live. Think of a little plant you saw or have at home, and tell me: Why are water and sunlight so important for this little plant to grow and look beautiful? Explain how you think the plant uses water and sunlight to make its food and stay alive.