Which reactions are heating and which are high temperatures in junior high chemistry?

There are relatively few high-temperature reactions in junior high school chemistry, and there are about three types.

1. Reduction of carbon. For example, reduced copper oxide, reduced iron oxide, etc. are all high temperatures.

2. Carbon monoxide reduces iron oxide. (This reaction is very important in the junior stage) Note: Reduced copper oxide is heated!

3. High-temperature calcined limestone.

Heating reaction:

Potassium chlorate and manganese dioxide are coheated to produce oxygen, potassium permanganate is heated to produce oxygen, hot copper reacts with oxygen, and carbon monoxide reduces copper oxide.

The reduction of metal oxides with carbon requires high temperatures and calcining limestone.

Carbon reacts with carbon dioxide.

Carbon reacts with water vapor

It's all high temperatures (these are generally the main ones in junior high school).

Reducing metal oxides with hydrogen is sufficient. The decomposition reflects that it is generally necessary to heat,

Carbon reduction of metal oxides, carbon monoxide reduction of iron oxide (blast furnace ironmaking), carbon and carbon dioxide reaction (the only endothermic reaction in junior high school), decomposition of calcium carbonate to high temperature, carbon monoxide reduction of copper oxide, sample its reaction with copper for heating.

I'm in my third year of junior high school.

Of all the reduction equations that have been contacted, only the CO,H2 reduced copper oxide is heated.

CO+CuO==(Heating)Cu+CO2, H2+CuO==(Heating)Cu+H2OEverything else is high temperature conditions (summarized by the teacher).

In other titles, there is a picture of the gift, and there is an alcohol lamp that is heated. Adding a grille is a high temperature. Alcohol blowtorches are also at high temperatures.

Especially when using carbon and carbon monoxide for reduction reactions, sometimes it is heated and sometimes it is high!

The high temperature is higher than the temperature at which it is heated.

When carbon is used as a reducing agent, because it is a solid and has a small contact area, it requires high conditions, high temperature, and carbon monoxide is a gas, which is easier to react, and is generally heated.

Junior high school needs high temperatures.

1 Carbon vs. carbon dioxide.

2 Carbon and copper oxide.

3 Decomposition of calcium carbonate.

Most of the substances react with charcoal at high temperatures, and with CO they are heated (iron removal reacts with CO).

Example: C+CO2 = High temperature 2Co

The heating is generally less than 1000 degrees Celsius.

The high temperature is generally above 1000 degrees Celsius.

The specific reaction equations, it is recommended that you memorize them carefully, there are not a few chemical equations in junior high school, and it is not as difficult as you think.

If there is charcoal, it will be high-temperature, and there is a special one that is high-temperature calcined limestone!

Remember the experiment

It is heated with an alcohol lamp.

Blowtorch with alcohol is high temperature.

Like what calcined limestone is high temperature.

Generally, the reaction produced in the laboratory is heated.

The industrial ones are all high temperatures.

The heating is generally below 600 degrees Celsius.

The high temperature is generally above 600 degrees Celsius.

Exothermic reactions are:

1. Combustion reaction.

2. Most of the chemical reactions.

3. Acid-base neutralization reaction.

4. Metal reacts with water or acid.

The endothermic reactions are:

1. Most of the decomposition reactions.

2、c+co2=2co

1.The direct heating includes: (1) laboratory preparation of O2, NH3, CH4, (2) H2 reduction of CuO, (3) NaHCO3 thermal decomposition, (4) metal and S reaction, (5) Cu reaction with concentrated H2SO4.

6) aldehyde reaction with newly prepared Cu(OH)2, (7) hydrolysis of halogenated hydrocarbons, (8) esterification reaction of alcohols and esters.

2.The asbestos mesh is heated with: (1) laboratory preparation of Cl2, HCl, C2H4, (2) Na combustion in air, (3) fractionation of petroleum.

3.Heated with a water bath, there are: (1) nitrification reaction between benzene and concentrated HNO3, sulfonation reaction with concentrated H2SO4, (2) silver mirror reaction between aldehyde and silver ammonia solution, and (3) reaction between formaldehyde and phenol.

Sodium is burned in oxygen, sodium bicarbonate is pyrolytic, sulfur and copper are heated and reacted, sulfur and iron are heated, NH4HCO3 is pyrolytic, NH4Cl crystals are heated, FeO is heated in air, and the following thermite reactions are undertaken: aluminum powder and iron oxide; aluminium powder and magnetic iron oxide; aluminum powder and manganese dioxide; The red-hot wire is extended into the gas collector containing chlorine gas to produce brownish-yellow smoke, which is shaken with water to produce a yellow solution; Reaction of red-hot iron with water vapor,

One. The main exothermic reactions that junior high school requires to know are:

1.All combustion reactions (must be mastered).

2.The reaction of acids with metals (must be mastered).

Reaction with metal oxides (understood).

4.All the slow oxidation, such as iron rusting, brewing, food decay, respiration of people and animals and plants, etc.

Two. Endothermic reactions that junior high school needs to know.

High temperature ==2c0 (mastery).

High temperature ==cao+CO2 (understand).

Three. Junior high school needs to know about the thermal effects of the dissolution process.

When concentrated sulfuric acid is dissolved in water, the temperature of the solution increases.

After the ammonium salt is dissolved, the temperature of the solution decreases.

Common exothermic and endothermic reactions in junior high school chemical reactions:

Common exothermic reactions: all combustion reactions; Neutralization reaction ; Most chemical reactions ; Reactive metals react with water or acid; slow oxidation of substances ;

Common endothermic reactions: most decomposition reactions; c+co2＝2co；h2+cuo＝cu+h2o；c+ h2o＝co+h2；ba(oh)2 · 8h2o+2nh4cl=bacl2+2nh3↑+10h2o。

1. High beat pants warm and green to tease calcium carbonate.

2. Reduction reaction of carbon.

3. The counterattack with iron oxides (iron oxide, ferric oxide, etc.) is the same as these three in junior high school.

Question 1: Which chemical reactions are exothermic and endothermic in junior high school Chemical reactions are generally exothermic, and decomposition is generally endothermic, with the exception: the decomposition of hydrogen peroxide is exothermic.

Carbon dioxide is heat-absorbing through red-hot carbon, and these two exceptions are in junior high school. In addition, acid-base neutralization is exothermic.

Question 2: Which are exothermic and which are endothermic in junior high school chemical reactions Common exothermic and endothermic reactions in junior high school chemical reactions:

Common exothermic reactions: all combustion reactions; Neutralization reaction ; Most chemical reactions ; Reactive metals react with water or acid; slow oxidation of substances ;

Common endothermic reactions: most decomposition reactions; c+co2＝2co；h2+cuo＝cu+h2o；c+ h2o＝co+h2；ba(oh)2 ・ 8h2o+2nh4cl=bacl2+2nh3↑+10h2o。

Question 3: What are the common endothermic and exothermic chemical equations in junior high school? Common exothermic reactions in junior high school:

1) All combustion reactions; (2) neutralization reaction; (3) most chemical reactions; (4) Reactive metals react with water or acid; (5) Slow oxidation of substances.

Common endothermic reactions: (1) most decomposition reactions; (2)c+co2＝2co；h2+cuo＝cu+h2o；

c+ h2o＝co+h2；ba(oh)2 ・ 8h2o+2nh4cl==bacl2+2nh3↑+10h2o。

Question 4: What are the reactions (exothermic and endothermic) in junior high school chemistry? Exothermic:

1: Reactive metals and acids react with acids or water 2 Acid-base neutralization reactions 3 All combustion reactions 4 Most chemical reactions are also endothermics: 1 Reaction of barium hydroxide with ammonium chloride 2 Reaction of charcoal and carbon dioxide at high temperature to produce carbon monoxide 3 Decomposition reaction of most salts.

Heating refers to the process by which a heat source transfers heat energy to a colder object, making it hot.

Heating

Generally speaking, the temperature expressed by the heating macro generally refers to the temperature of the flame of the alcohol lamp, about 400 500, such as the decomposition temperature of NaHCO3 is 270, written as: 2NAHCO3==NA2CO3+H2O+CO2.

High temperatures

Temperatures above 500 °C are required to be achieved in the laboratory with an alcohol blowtorch or gas lamp. Alcohol blowtorch or adjust the normal gas lamp temperature up to 700 1000. This is commonly referred to as "high temperature".

For example, the decomposition temperature of CaCO3 is 825, which should be written as: CaCO3==CaO+CO2.

So the difference between heating and high temperature is the reaction temperature, and of course, like anything else, there is no absolute limit between heating and high temperature. Therefore, for some reactions with different products due to different temperatures, the specific temperature should be marked when writing the chemical equation. For example, ch3ch2ohch2=ch2 + h2o.