Find a complete set of high and high thermochemical equations, common thermochemical equations

In fact, thermochemical equations are not difficult to write. Just find the chemical equation and write it. 1. When writing, the temperature and pressure at the time of reaction must be indicated.

2. The right side of the chemical formula of each substance is indicated by a parenthetical bracket () indicating the aggregation state of the substance.

3. The stoichiometric number in the thermochemical equation only indicates the amount of the substance.

4· h can only be written on the right side of the chemical equation, if it is an exothermic reaction, then h is "-", if it is an endothermic reaction, then h is "+", and its unit is generally kj mol.

5. The thermochemical equation is the quantity that indicates the completion of the reaction.

6. Do not mark " " or " ".

7. The reaction conditions are not specified.

;△h=+1777kj/mol。

graphite) + O2 (g) = = CO2 (g); △h=。

h=-534kj/mol。

graphite) ==c (diamond); △h=+。

h=。△h=。

h=。△h=。

h=-853kj/mol。

h=。1) The ordinary chemical equation only indicates the change of matter in a chemical reaction; The thermochemical equation is a chemical equation that expresses the heat emitted or absorbed by the reaction, which indicates both the change of matter in the chemical reaction and the change of energy in the chemical reaction.

2) Note that the symbol and unit h can only be written on the right side of the chemical equation labeled with the state of reactants and products. If it is an exothermic reaction, h is "-" and if it is an endothermic reaction, h is "+" and the unit of h is generally kj moj.

3) Under the same conditions (temperature, pressure), the chemical reaction of the same substance (mutual inversion reaction, Sun Da blind is not necessarily a reversible reaction), the reaction of the ruler in the forward direction and the reaction carried out in the reverse direction, the reaction heat h value is equal, and the sign is opposite.

4) Note that the aggregation state of the substance, the aggregation state of the reactant and the product are different, and the heat of reaction h is different. Therefore, the aggregation state of the matter must be noted in order to fully reflect the significance of the thermochemical equation. "G" for gases and :: for liquids

l", "S" for solids, and "AQ" for solutions.

5) Regarding the comparison of the magnitude of the heat of reaction, pay attention to the understanding: there are two situations, one is to compare q (the heat is empty), then it is only related to the value of the heat of reaction, and has nothing to do with the " " symbol, " only indicates endothermic or exothermic; The second is to compare h, which is related to the " " symbol.

The thermochemical equation of high school chemistry is to express the change of substances and enthalpy changes in a chemical reaction, and the amount of reactants in the actual reaction is more than the required amount, but the state of the excess reactants does not change, so it does not affect the heat of reaction of the reaction. The molar enthalpy change of a chemical reaction at the standard state is called the standard molar enthalpy and is denoted by the symbol δFHMO.

The thermochemical equations of common high school chemistry equations are as follows.

caco3(s)+==cao(s)+co2(g);△h=+1777kj/mol

C(graphite)+O2(g)===CO2(g); △h=

C(diamond)+O2(g)===CO2(g); △h=

c (graphite) ===c (diamond); △h=+

naoh(aq)+hcl(aq)=nacl(aq)+h2o(l);△h=

c(s)+o2(g)==co2(g);△h=

co(g)+1/2o2(g)==co2(g);△h=

h2(g)+1/2o2(g)==h2o(g);△h=

n2h4(g)+o2(g)==n2(g)+2h2o(g);△h=-534kj/mol

s(s)+o2(g)==so2(g);△h=-297kj/mol

fes2(s)+11/4o2(g)==1/2fe2o3(s)+2so2(g);△h=-853kj/mol

so2(s)+1/2o2(g)==so3(g);△h=

3h2(g)+n2(g)==2nh3(g);△h=

2o2(g)+n2(g)==2no2(g);△h=+68kj/mol

o2(g)+n2(g)==2no(g);△h=-kj/mol

naoh(aq)+1/2h2so4(aq)=1/2na2so4(aq)+h2o(l);△h=

Precautions for writing thermochemical equations of common high school chemistry equations.

1) The heat of reaction is related to the measurement conditions such as temperature and pressure, so the temperature and pressure at the time of reaction are indicated when writing.

2) H can only be written on the right side of the chemical equation, if it is an exothermic reaction, then h is "-", if it is an endothermic reaction, then h is "+", and its unit is generally kj mol. For the same chemical reaction, if the stoichiometric number is different, the value of h is different.

If the stoichiometric number is the same, the value of h is also different when the state of the reactant and product is different.

3) Do not mark " " or " ".

4) Thermochemical equations generally do not need to write reaction conditions, e.g. (heating), because the aggregation state is marked.

5) The organic thermochemical equation is "=", not "".