The third question is why hydrogen can t be brought in directly

Because the title said that there are two forms of magnesium in the magnesium bar, one is magnesium oxide, the other is magnesium element, the amount of magnesium element can be calculated by the amount of hydrogen, and the magnesium content in the magnesium oxide needs to be calculated, and then the magnesium content in the magnesium bar is calculated.

Solution: (1) f(x) = x power of m·e - lnxf (x) = x power of m·e - 1 x

The extreme point is the point where the derivative is zero.

f (x) = m · e to the power of x - 1 x = 0

f＇(1)=m·e -1 =0

m = 1 ef(x) = x power of 1 e·e - x - x-1 power of lnx = ·e - lnxf(x) = x - power of e - lnx

When x 1 f (x) 0 function is an increasing function.

When 0 x 1 f (x) 0 function is a subtraction function.

When x 0 f (x) 0 function is a subtraction function.

where 0 is the discontinuity point.

2) f(x) = m·e to the power of x-lnx

When m 1 e2 f(x) = x power of m·e - x power of lnxm·e - lnx 1 power x of e2·e - lnxf(x) 1 power x of e2·e - power of x - lnx = x of e - x-power of lnxf(x) x of e - lnx - lnx

From the image f(x)=e to the x-2 power.

f(x)=lnx

The above two images never intersect, and the x-2 power of f(x)=e is always above f(x)=lnx.

x-2 power of e-lnx 0 f(x) 0

Hello dear, hydrogen is difficult to transport mainly for the following reasons:1Combustibility of hydrogen:

Hydrogen is a highly flammable and explosive gas, once leaked, it is very easy to cause disasters and disasters, which greatly threatens the lives and property of people in Qinxun. 2.Low density of hydrogen:

Compared with general fuels, such as gasoline and diesel, hydrogen is much lighter in mass than volume, so it needs to be compressed and liquefied to improve its density to a certain extent, but this will also increase the cost and complexity of hydrogen transportation and storage. 3.Permeability of hydrogen:

Unlike ordinary gases, hydrogen is very permeable, and it is difficult to avoid hydrogen leakage when transported in conventional containers, and it is difficult to maintain high pressure and stability during transportation. Therefore, there are still some technical problems to be solved in the logistics, storage and transportation of hydrogen energy.

The body is unable to absorb hydrogen because we lack the corresponding enzymes to break down and metabolize hydrogen molecules. Although hydrogen is considered a very good antioxidant in some ways, there is not enough mechanism in the human body to dismantle it.

In general, our bodies need to convert food into nutrients such as proteins, carbohydrates, and fats to be able to absorb and utilize them. These nutrients are broken down into small molecules that can be used by cells during digestion and then transported to various parts of the body through the bloodstream. Hydrogen is not one of the nutrients our body needs, and there is no pathway similar to digesting and metabolizing other nutrients for the body to absorb and utilize it.

In addition, experiments have shown that hydrogen is relatively permeable, and even if a person inhales hydrogen directly, most of the hydrogen molecules remain in the lungs and cannot enter the blood circulation. Therefore, although there is a lot of research on hydrogen, further in-depth research and exploration is needed to truly use it as a means of human health.

There will be a special hydrogen tank for hydrogen injection, if it is a person, it is recommended not to operate it easily, because the chemical properties of hydrogen are unstable, it is easy to cause combustion**.

It is recommended not to let children play with hydrogen balloons, and to choose safer helium balloons. Hydrogen is not poisonous, but it is dangerous for babies to play with hydrogen balloons, and there have been many reports. When the hydrogen balloon encounters static electricity, open flames, sun exposure or high-temperature objects, it will occur, and the baby's body will be damaged to varying degrees, so pay attention to safety when playing.

Hydrogen is not easy to store, and is generally obtained by splitting water and electrolyzing sodium chloride solutions. Using hydrogen as fuel, it contributes to desert management. Hydrogen produced in large quantities is transported to the edge of the desert as fuel, and the combustion product is water, which can be used for irrigation.

Large amounts of hydrogen can be burned to provide energy for greenhouses, where saplings can be planted, grass seeds can be cultivated, trees and grasses can be planted in desert environments outside greenhouses, and windbreak and sand fixation can be carried out.

Because dilute nitric acid has strong oxidative free coarseness, the reaction between Shenji and metal generally generates water instead of hydrogen, and the replacement reaction to produce hydrogen is generally carried out by reacting with more active metals and dilute sulfuric acid or dilute hydrochloric acid

Therefore, the stool model is selected A