Which is greater than the heat released by magnesium combustion or the heat released by magnesium re

Solution: MGO can be found in the thermodynamic table.

The standard heat of generation for MGO is.

Standard heat of generation for Mg2+.

The standard heat of generation for H+ is 0

The standard heat of formation of the stable elemental is 0

According to mg(s)+1 2o2(g)=mgo(s), its enthalpy becomes.

According to mg(s)+2h+(aq) = mg2+(aq) +h2(g), the enthalpy becomes .

Because the enthalpy change of the former is smaller than that of the latter, the heat released by the reaction of mg with oxygen is greater than that of its reaction with acid.

Note: Under standard conditions.

The landlord still has a good review, check the definition of calorific value, mg only corresponds to the only calorific value, and the Gaisce's law upstairs is very exciting, but unfortunately the hydrogen produced by the reaction with the acid is not considered, resulting in a deviation in the results.

Name: Magnesium oxide

Commonly known as: bitter soil; Lamp powder.

Molecular Formula: MGO

Physical properties: white easy powder, odorless, tasteless, this product is insoluble in water and ethanol, melting point 2852, boiling point 3600, magnesium oxide has high fire resistance and insulation properties.

Chemical properties: Magnesium oxide is an alkaline oxide with the general properties of alkaline oxides.

Exposed to air, it easily absorbs water and carbon dioxide, and dissolves in acids and ammonium salts.

mgo+2hcl===mgcl2+h2o

mgo+nh4cl===mgcl2+nh3+2h2o

It slowly interacts with water to form magnesium hydroxide.

Classification: There are two kinds of light magnesium oxide and heavy magnesium oxide. Lightweight, fluffy, white amorphous powder.

Odorless, tasteless, non-toxic. Density 3 58g cm3. It is insoluble in pure water and organic solvents, and its solubility increases due to the presence of carbon dioxide in water.

Soluble in acid, ammonium salt solution. It is converted into crystals by high-temperature burning. When exposed to carbon dioxide in the air, magnesium carbonate double salt is formed.

Heavy and compact in size, white or beige powder. It is easy to combine with water, and it is easy to absorb moisture and carbon dioxide in the exposed air. It is easy to gel and harden when mixed with magnesium chloride solution.

Applications: Lightweight magnesium oxide is mainly used as a raw material for the preparation of ceramics, enamels, refractory crucibles and refractory bricks. It is also used as a polishing agent, binder, url] coating] and filler for paper, accelerator and activator for neoprene and fluoroelastomer.

After mixing with magnesium chloride and other solutions, it can be made into magnesium oxide water adjustment. It is used as an antacid and laxative in medicine, used in hyperacidity, gastric and binal ulcer disease, and used as a catalyst and raw material for the manufacture of magnesium salts in the chemical industry. It is also used in the manufacture of glass, dyeing meal, phenolic plastics, etc.

Heavy magnesium oxide is used in the rice milling industry for firing, grinding and half drums. It is used in the construction industry to manufacture artificial chemical flooring, artificial marble, heat proof panels, sound insulation panels, and plastic industries as fillers. It can also be used in the production of other magnesium salts.

It is mainly used to prepare internal medicine to neutralize excessive stomach acid. Commonly used preparations are: magnesia emulsion - emulsion; Magnesium cover tablets – each tablet contains; Acid powder - a powder made of magnesium oxide and sodium bicarbonate.

The magnesium oxide produced by the sea magnesium chemical plant is highly active, but many people misunderstand that the content and activity of magnesium oxide are directly proportional to a range beyond this range, and it is inversely proportional beyond this range!

Now magnesium oxide is misunderstood by most people as light burnt powder, in fact, this understanding is wrong, light burnt powder can be said to be a kind of magnesium oxide, its alias is also called light burnt magnesium, light burnt magnesium oxide, water chestnut soil, bitter soil powder (Japanese transliteration), magnesium calcium powder (because light burnt powder contains calcium oxide) In the building materials industry, the lower the calcium oxide content in the light burnt powder, the better!

In the same way, in these two reactions, mg changes from 0 valence to +2 valence, and the gain and loss of electrons in this process is the same, so the energy should also be the same, and we will feel that the energy is different, but the manifestation and intensity of the energy are different.

Of course, it is more radiant to react with acid, because magnesium oxide can react with acid, and it is an exothermic reaction.

It is not the same, because the essence of a chemical reaction is the breaking of the chemical bond (energy absorption) and the formation of the chemical bond (releasing energy), and both reactions have breaking and forming, so it is difficult to judge. Judging by feelings is wrong. Calculations or experiments should be performed based on the data provided.

Magnesium is burned because ignition agents such as potassium chlorate and magnesium strips are required before the thermite reaction occurs. The highest point of activation energy for ultra-high thermite reactions. This reaction is exothermic and can be carried out autonomously from the beginning.

mg burns big, maybe because I don't know how much it weighs.

Exothermic. The chemical equation for the chemical reaction of magnesium and hydrochloric acid is: mg+2HCl=mgCl2+H2. The experimental phenomenon is as follows: magnesium is gradually dissolved, a large number of bubbles are rapidly generated on the surface of magnesium, and the outer wall of the test tube is heated. The type of reaction is displacement reaction.

Magnesium has strong reducibility, can react with boiling water to release hydrogen, can produce dazzling white light when burning, magnesium and fluoride, hydrofluoric acid and chromic acid do not react, and are not subject to caustic erosion, but it is easily soluble in organic and inorganic acids, magnesium can be directly combined with nitrogen, sulfur and halogens, including hydrocarbons, aldehydes, alcohols, phenols, amines, lipids and most oils, including organic chemicals and magnesium only slightly or not at all.

Magnesium and halogenated hydrocarbons react violently under anhydrous conditions (Grignard reagent is generated), magnesium can burn with carbon dioxide, so magnesium combustion cannot be extinguished with carbon dioxide fire extinguishers. Because magnesium can react with N and O, when magnesium is burned in the air, it burns violently and emits dazzling white light, which is exothermic and generates a white solid. In vinegar, bubbles emerge quickly, float on the vinegar surface, and gradually disappear.

Some fireworks and flares contain magnesium powder, which takes advantage of the dazzling white light that magnesium emits when burned in the air. The valency of magnesium in chemical reactions is usually +2 valence.

The reaction of magnesium strips and dilute hydrochloric acid is exothermic. In a chemical reaction, a reaction in which the total energy of the reactants is greater than the total energy of the products is called an exothermic reaction. These include combustion, neutralization, metal oxidation, thermite reactions, more active metal and acid reactions, and reactions from unstable substances to stable substances.

Dilute hydrochloric acid, i.e., before hydrochloric acid with a mass fraction of less than 20%, the chemical formula of the solute is HCl. Dilute hydrochloric acid is a colorless, clear liquid that is strongly acidic. It is a pharmaceutical excipient, and the pH value is adjusted to a high knot, which should be sealed and stored in a glass bottle.

It is mainly used for laboratory production of carbon dioxide and hydrogen, to remove scale, and for medicinal purposes, it can mainly be used for achlorhydria.