Equation 10 for excessive small quantities, equations for excessive quantities

4Hno3+ Fe (less) = Fe (No3) 3 + No(G) + 2H2O8Hno3+ 3Fe (over) = 3Fe (No3) 2 + 2 No(G) + 4H2O

The reason is that +3-valent Fe can oxidize +2-valent Fe

The reduction product of dilute nitric acid is generally considered to be NO, and the reduction product of concentrated nitric acid is NO22Fe(NO3)3 + 6HI (less) = 6NO(G) + 2Fe(IO3)3+3H2O

At this time, only Hno3 is used to oxidize the I ion.

Fe(NO3)3+ 4HI(over)=Fe(NO3)2+2I2+NO(G)+2H2O

At this time, Hno3 and +3 valent Fe and the resulting iodate group can oxidize I ions.

Both dilute and concentrated Hno3 have strong oxidizing properties, and there can be no H2 reaction in the product, and the equation is as follows:

Fe + 4Hno3 (dilute) = Fe (No3) 3 + No (gas) + 2H2O

Fe+6Hno3 = Fe(No3)3 + 3NO2 (gas) +3H20

Reducibility: I->Fe2+>br-

Fe3+ is oxidizing.

i- Fe3+ can be reduced to Fe2+

Ferric nitrate, less 3 in the lower right corner of nitrate?

2Hno3+ Fe==Fe(NO3)2+H2 (ascending sign) A small amount.

2Hno3 + Fe = Ferrous nitrate + water excess.

The equation represents a chemical reaction, and when there is a question of quantity, it depends on whether the reaction is finished. When writing an equation for a small amount of excess, it is necessary to correctly judge the product based on a small amount of quantity, and finally use conservation to balance it. At the time of trimming, the coefficient of a small amount of substance is positioned at 1, and then the other coefficients are matched.

When a fraction appears, multiply it by the least common multiple.

For example, sulfur dioxide and sodium hydroxide, SO2 is an acidic oxide, acid is H2SO3, and when a small amount of SO2 is used, the product is a positive salt; In excess, it is an acid salt.

When a small amount of sulfur dioxide is used, the reaction is: SO2 + 2 NaOH = Na2SO3 + H2O;

In excess of SO2, SO2 + NaOH = NaHSO3

Mark (over) in the lower right corner of the chemical reactant. A small amount is marked as an excess of another substance.

1. The amount is different. The difference between the three can be seen from the literal meaning, a small amount indicates that there are fewer reaction reagents, a sufficient amount indicates that the reaction reagents are sufficient, and an excess indicates that there is a surplus of reaction reagents.

2. The amount of product generated is different. A small amount of reaction products is produced with less, while both sufficient and excessive amounts can result in more reaction products.

3. The degree of reaction is different. A small amount indicates that the reaction is carried out to a small extent, and the reaction is insufficient, and a sufficient amount indicates that the reaction has just been completed, but the product may be in the mixture, and the excess must make the reaction occur in the direction of the reduction of the energy of the product, and the reaction is sufficient.

A small amount of substances participate in the reaction, if the reaction can be divided into several steps, such as carbon dioxide and sodium hydroxide can be combined into sodium carbonate and water, and then sodium bicarbonate is generated, a small amount of carbon dioxide is only the first step of the reaction, only sodium carbonate is generated. Adequate and excessive means that there is still a residue of the substance after all possible reactions have been completed. If excessive carbon dioxide is introduced into sodium hydroxide, sodium bicarbonate will be generated.

Usually when it is mentioned that there is an excessive amount and a small amount, it is likely that the reaction is not the same, to give lz as an example, the reaction process of adding hydrochloric acid to sodium carbonate is as follows.

When I first started adding na2co3

hclnacl

nahco3

After all the sodium carbonate is generated into sodium bicarbonate, the addition of hydrochloric acid will result in the reaction of NaHCO3 as follows

hclnacl

H2OCo2 gas.

This is the whole reaction process, simply put, there is an excess of sodium carbonate at the beginning, so CO2 gas will not be released when hydrochloric acid is just added.

The addition of sodium carbonate to hydrochloric acid is the opposite, and at the beginning there is an excess of hydrochloric acid, so only one step of Na2CO3 reaction is carried out

2hcl2nacl

H2OCo2 gas.

If you don't understand anything, please ask, thank you for adopting!

This requires a chemical equation to be balanced: for a simple example: 2H2+O2=2H2O, let's take this equation for example.

If both are 1mol of H2 and O2, you can see at a glance: H2 is insufficient, O2 is excessive, how do you see it? Because of the trimming of the chemical equation above.

Sufficient amount of aluminum ions and a small amount of hydroxide reaction:

al3+ +3oh- =al(oh)3

Sufficient hydroxide and a small amount of aluminum ions for reaction:

Al3+ +4OH- =AlO2- +2H2O2NaOH+CO2=Na2CO3+H2O CO2 is not excessive.

2NaOH + 2CO2 + H2O = 2NaHCO3 CO2 excess small amount: 2 NaAlO2 + CO2 + 3 H2O = 2Al(OH)3 Na2CO3

Overdose: Naalo2 + CO2 + 2H2O = Al(OH)3 + NaHCO3

The coefficient in the equation is generally 1 for a small amount of a substance, and the coefficient for reactants other than the excess is generally 1 in the case of excess

The equation product of a small amount of reaction can generally be rereacted with its reactants.

For example: 2NaOH+CO2=Na2CO3+H2O (a small amount of carbon dioxide) and Na2CO3+CO2+H2O=2NaHCO3

Excess carbon dioxide: NaOH + CO2 = NaHCO3

"Less definite and more variable" such as Al3+ and a small amount of OH-, OH- less, fixed - 1mol, need one-third Al3+, change.

For example, Al3+ and excess OH-, Al3+, less, fixed - 1mol, need 4moloh- change.

Usually when it comes to an excessive amount of a small amount, it is very likely that the reaction is different, so let's give an example of lz.

The reaction process of adding hydrochloric acid to sodium carbonate is as follows.

At the beginning of the addition, Na2CO3 + HCl = NaCl + NaHCO3

After all the sodium carbonate is generated into sodium bicarbonate, the following reaction will be followed by the addition of hydrochloric acid.

NaHCO3 + HCl = NaCl + H2O + CO2 gas.

This is the whole reaction process, simply put, there is an excess of sodium carbonate at the beginning, so no CO2 gas is released when hydrochloric acid is added to the spine limb.

The addition of sodium carbonate to hydrochloric acid is the opposite, and at the beginning there is an excess of hydrochloric acid, so only one step of the reaction is carried out.

Na2CO3 + 2HCl = 2NaCl + H2O + CO2 gas.

If you don't understand anything, please ask, thank you!

This requires a chemical equation: a simple example: 2H2+O2=2H2O, let's take the equation of the manuscript bend as an example.

If they are both 1mol of H2 and O2, you can see at a glance: H2 is insufficient, O2 is excessive, how do you see it? ? Because of the trimming of the chemical equation above.

This should be seen according to the reaction of different letter oaks.

For the general grip, in front of the excess substance, its coefficient becomes 2 times that of another substance!

I'm sorry, I may not be clear, I'm also a high school student, let's analyze it according to the specific problem!

The proportion of a small number of ions must be the same as before the reaction.