Find the writing of several chemical reaction equations

Calcium oxide reacts with carbon dioxide.

CAO+SIO2 High Temperature CasIO3

Calcium carbonate reacts with carbon dioxide and water.

CaCO3 + CO2 + H2O = Ca(HCO3)2 introduces carbon dioxide gas into the sodium carbonate solution.

Na2CO3 + CO2 + H2O = 2NaHCO3 introduces carbon dioxide gas into the sodium hydroxide solution.

In the case of a small amount of CO2, the reaction is 2NaOH + CO2 = Na2CO3 + H2O

In case of excess CO2, the reaction is NaOH + CO2 = NaHCO3 Silica reacts with sodium hydroxide.

SiO2 + 2NaOH = Na2SiO3 + H2O Sulfur dioxide reacts with sodium hydroxide.

If there is a small amount of SO2, the reaction is 2NaOH + SO2 = Na2SO3 + H2O

In case of excess SO2, the reaction is NaOH + SO2 = NaHSO3 sulfur trioxide reacts with sodium hydroxide.

2NaOH + SO3 = Na2SO4 + H2O sulfur trioxide reacts with water.

so3 + h2o = h2so4

CAO+SIO2 High Temperature CasIO3

CaCO3+H2O+CO2=Ca(HCO3)2Na2CO3+H2O+CO2=2NaHCO3 (if it is a saturated sodium carbonate solution, the precipitation symbol needs to be written, and the solubility of sodium bicarbonate is less than that of sodium carbonate).

2naoh+co2=h2o+na2co3

sio2+2naoh=na2sio3+h2oso2+2naoh=na2so3+h2o

so3+2naoh=na2so4+h2o

so3+h2o=h2so4

CaO+CO2 = (high temperature) CaCO3

CaCO3 + CO2 + H2O = Ca(HCO3)2Na2CO3 + CO2 + H2O = 2NaHCO32NaOH + CO2 (insufficient) = Na2CO3 + H2ONaOH + CO2 (sufficient) = NaHCO3

2NaOH + SiO2 = Na2SiO3 + H2O2NaOH + SO3 (insufficient) = Na2SO4 + H2OnAOH + SO3 (sufficient) = NaHSO4

so3+h2o=h2so4

a+b===c+d or a+b===c, e.g. 2h2

O2 = Ignition = 2H2O

Note: Only the answer indicates the reaction conditions, Li He, with the direction of the first mountain, Chi Ping and the arrow.

ab==c,, as in 2h2

O2 = Ignition = 2H2O

Take care to indicate the reaction conditions and trim.

Chemical equations are difficult for a junior high school student. In order to write the chemical equation correctly, you should master the following aspects:

1. Element symbols to remember. 2. The chemical formula should be written correctly, and the valency should be remembered if the chemical formula is written correctly.

3. Learn to balance chemical equations.

Note: Valency memory mouth is fast; Monovalent hydrochloride, potassium, sodium, silver, barium oxide, calcium, magnesium, zinc, 246, sulfur, 244, 6, 24, 6, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 2, 2, 2, 6, 2, 2, 2, 6, 2, 2, 6,

The methods of balancing chemical equations are;

1. Least common multiple method, for example: P+O2==P2O5 The least common multiple of 2 and 5 is 10, 10 divided by 2 to get 5 is the coefficient of O2r, and 10 divided by 5 to get 2 is the coefficient.

2. Observation method, e.g. Fe+O2 - Fe3O4

3. Set a method, that is, set the coefficient of a substance as one, calculate the other coefficients, and multiply the denominator if there is a fraction, and remove the denominator. For example, C2H2+O2 - CO2 + H2O 1C2H2 + 5 2O2 - 2CO2 + 1H2O 2C2H2 + 5O2 ===4CO2 + 2H2O

That is, the chemical reaction is an experimental fact, and the equation is only used to record and represent, that is to say, there will be a corresponding equation with a chemical reaction, or it is your own conjecture, the equations you have learned so far are to be remembered, there are some principles in it, such as acid energy and alkali reaction, that is, the -oh and -h in it are synthesized into water, you will remember HCl+Naoh=NaCl+H2O, not because you really understand the truth, but just remember it, The fact of the experiment is that these two things react together, and it turns out that the product is these two.

Take the example of hydrogen reacting with oxygen to produce water:

The chemical reaction formula is H2 + O2 H2O

The chemical equation is 2H2 + O2 = 2H2O, and the literal expression is hydrogen + oxygen and water.

There is no trim for the chemical reaction formula Buqing, so the equal sign cannot be used in the middle, and the arrow is changed to the equal sign after the reaction type is balanced.

For example, c+O2=CO2 chemical anti-filial piety, such as the implicit formula, the chemical equation, the literal expression is carbon + oxygen hall gas = carbon dioxide.

1. Bromine atom replaces 1 h atom.

2. Hydrogen bromide is added to the double bond, and H is added to C by the benzene ring.

3. Oxidation to terephthalic acid.

4. OH substitution of chlorine atom position.