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Anonymous users2024-02-05The teacher should have said that you should pay attention to the summary at ordinary times. Know the type of chemical reaction, and be familiar with the reaction that substances can perform, for example, some metals can react with non-metals and can react with salts, non-metal oxides, etc., the content is more miscellaneous, usually to summarize, the exam will generally have prompts, it is calculated that there is no judgment based on the knowledge learned, the teacher will teach. If there is a reaction, remember the type of chemical reaction, different types of products are different compounds:
Two or more substances form one substance. Decomposition: The decomposition of a substance into two or more substances.
Displacement: The reaction of one element and one compound to produce another element and another compound. Metathesis:
One compound reacts with another and is exchanged with each other. It is also necessary to divide organic and inorganic, the basic reactions are almost the same, and the organic substances may be complex, which requires the basic substances, the types of functional groups, and the main reactions that can occur in functional groups, which is actually very simple. Relatively inorganic inferences are more difficult than organic.
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Anonymous users2024-02-041.Looking at your usual summary and accumulation, some of them are wrong at first glance.
2.Summarize the relationships between substances that can be reflected, and list the same substances together.
3. Summarize common ionic reactions, because ionic reactions can summarize a large number of reaction laws.
4.Summarize some common micro-contents and do not tolerate things.
After accumulating over time, I believe that the landlord's chemistry will go to the next level.
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Anonymous users2024-02-03The general reaction mainly depends on the usual accumulation, and the metathesis reaction must meet one of the three conditions.
Generate water, produce gas, and generate precipitation.
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Anonymous users2024-02-02Detect whether the law of conservation of mass is followed by the test of mass or by calculation.
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Anonymous users2024-02-01The condition of the metathesis reaction is that a precipitate or gas or a weak electrolyte can be generated.
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Anonymous users2024-01-31The formula determines whether the reaction can proceed spontaneously: g= h t s. g is the Gibbs free energy change, h is the enthalpy change, s is the entropy change, and t is the Kelvin temperature.
Under the condition of certain temperature and pressure, the interpretation of chemical reaction is based on:
The h-tδs<0 reaction can proceed spontaneously.
The h-tδs=0 reaction reaches an equilibrium state.
The h-tδs>0 reaction cannot proceed spontaneously.
Note: (1) When ΔH is negative and ΔS is positive, any temperature reaction can proceed spontaneously.
2) When δh is positive and δs is negative, no temperature reaction can be carried out spontaneously.
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Anonymous users2024-01-30This is to distinguish between the two substances.
There is it depending on the type of reaction.
Ionic reaction: Reaction can be done when there is a precipitate, gas, or substance that is difficult to ionize.
Redox reaction: A substance has oxidation, and a substance can react if it has reductivity.
First of all. Two substances react.
If it can generate CaCO3, BaCO3, BaSo4 and other precipitated ones, it can be reacted.
For example, NaCl and AgNO3 generate AGCL precipitates.
Hence the reaction.
Secondly. If H2O can be generated, substances that are difficult to ionize, such as CH3COOH, can also be reacted.
For example. NaOH and H2SO4 can generate H2O, so they can react.
And also. Substances that can generate gases such as CO2 and H2 can also react.
For example, Na2CO3 and H2SO4 can generate CO2, which can react.
This part is the principle of the reaction in the solution.
As for redox reactions.
Oxidizing substances are mainly.
O2, Cl2, Br2, Fe3+, KmNO4, etc.
Reducible substances are mainly.
S2-, Na, K, Cl-, Fe2+, etc.
When oxidizing and reducing substances are present at the same time.
A reaction will occur.
For example. Cl2+FeCl2 will produce FeCl3
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Anonymous users2024-01-29To put it simply, it is to see whether there is precipitation, gas formation, whether the color and properties have changed, and whether there is a change in temperature.
The most fundamental thing is to check whether the original chemical properties of the substance have changed.
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