# Chemical equation

**chemical equationsequationequationsbalancebalancedbalanced chemical equationchemicalhalf-reaction be balancedionic equationmolecular equation**

A chemical equation is the symbolic representation of a chemical reaction in the form of symbols and formulae, wherein the reactant entities are given on the left-hand side and the product entities on the right-hand side.wikipedia

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### Chemical reaction

**reactionchemical reactionsreactions**

A chemical equation is the symbolic representation of a chemical reaction in the form of symbols and formulae, wherein the reactant entities are given on the left-hand side and the product entities on the right-hand side.

Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the nuclei (no change to the elements present), and can often be described by a chemical equation.

### Product (chemistry)

**productsproductchemical products**

A chemical equation is the symbolic representation of a chemical reaction in the form of symbols and formulae, wherein the reactant entities are given on the left-hand side and the product entities on the right-hand side.

When represented in chemical equations products are by convention drawn on the right-hand side, even in the case of reversible reactions.

### Chemical formula

**formulamolecular formulageneral formula**

A chemical equation consists of the chemical formulas of the reactants (the starting substances) and the chemical formula of the products (substances formed in the chemical reaction).

Chemical formulas may be used in chemical equations to describe chemical reactions and other chemical transformations, such as the dissolving of ionic compounds into solution.

### Sodium chloride

**NaClsaltroad salt**

Using IUPAC nomenclature, this equation would be read as "hydrochloric acid plus sodium yields sodium chloride and hydrogen gas."

It is the starting point for the chloralkali process, which provides the world with chlorine and sodium hydroxide according to the chemical equation

### Chemical equilibrium

**equilibriumchemical equilibriaequilibria**

"" symbol is used to denote an equilibrium..

In the following chemical equation with arrows pointing both ways to indicate equilibrium, A and B are reactant chemical species, S and T are product species, and α, β, σ, and τ are the stoichiometric coefficients of the respective reactants and products:

### Jean Beguin

The first chemical equation was diagrammed by Jean Beguin in 1615.

In the 1615 edition of his textbook, Beguin made the first-ever chemical equation or rudimentary reaction diagrams, showing the results of reactions in which there are two or more reagents.

### Aqueous solution

**aqueouswater solubilityaqueous solutions**

When stating physical state, (s) denotes a solid, (l) denotes a liquid, (g) denotes a gas and (aq) denotes an aqueous solution.

It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula.

### Spectator ion

**spectator ions**

Because such ions do not participate in the reaction, they are called spectator ions.

A spectator ion is an ion that exists as a reactant and a product in a chemical equation.

### Reagent

**reactantreagentsreactants**

A chemical equation is the symbolic representation of a chemical reaction in the form of symbols and formulae, wherein the reactant entities are given on the left-hand side and the product entities on the right-hand side.

### Arrow (symbol)

**arrowsarrowArrows in Unicode**

The two are separated by an arrow symbol (\rightarrow, usually read as "yields") and each individual substance's chemical formula is separated from others by a plus sign.

### Plus and minus signs

**minus signplus sign+**

The two are separated by an arrow symbol (\rightarrow, usually read as "yields") and each individual substance's chemical formula is separated from others by a plus sign.

### Hydrochloric acid

**HClhydrochloricmuriatic acid**

As an example, the equation for the reaction of hydrochloric acid with sodium can be denoted:

### Sodium

**NaNa + sodium ion**

As an example, the equation for the reaction of hydrochloric acid with sodium can be denoted:

### IUPAC nomenclature of chemistry

**IUPAC nameChemical namenomenclature**

But, for equations involving complex chemicals, rather than reading the letter and its subscript, the chemical formulas are read using IUPAC nomenclature.

### Hydrogen

**HH 2 hydrogen gas**

Using IUPAC nomenclature, this equation would be read as "hydrochloric acid plus sodium yields sodium chloride and hydrogen gas."

### Diatomic molecule

**diatomicdiatomic moleculesdi-**

This equation indicates that sodium and HCl react to form NaCl and H 2 . It also indicates that two sodium molecules are required for every two hydrochloric acid molecules and the reaction will form two sodium chloride molecules and one diatomic molecule of hydrogen gas molecule for every two hydrochloric acid and two sodium molecules that react.

### Charge conservation

**conservation of chargeConservation of electric chargecharge**

The stoichiometric coefficients (the numbers in front of the chemical formulas) result from the law of conservation of mass and the law of conservation of charge (see "Balancing Chemical Equation" section below for more information).

### Stoichiometry

**stoichiometricstoichiometric coefficientstoichiometries**

The stoichiometric coefficients (the numbers in front of the chemical formulas) result from the law of conservation of mass and the law of conservation of charge (see "Balancing Chemical Equation" section below for more information). The coefficients next to the symbols and formulae of entities are the absolute values of the stoichiometric numbers.

### Conservation of mass

**law of conservation of massconservation of mattermass conservation**

The stoichiometric coefficients (the numbers in front of the chemical formulas) result from the law of conservation of mass and the law of conservation of charge (see "Balancing Chemical Equation" section below for more information).

### System of linear equations

**systems of linear equationslinear system of equationssimultaneous linear equations**

Another technique involves solving a system of linear equations.

### Fraction (mathematics)

**denominatorfractionfractions**

If any fractional coefficient exists, multiply every coefficient with the smallest number required to make them whole, typically the denominator of the fractional coefficient for a reaction with a single fractional coefficient.

### Kernel (linear algebra)

**kernelnull spacenullspace**

Any vector which, when operated upon by the composition matrix yields a zero vector, is said to be a member of the kernel or null space of the operator.

### Rank (linear algebra)

**rankcolumn rankfull rank**

In other words, the rank (J R ) of the composition matrix is generally less than its number of columns (J). By the rank-nullity theorem, the null space of a ij will have J-J R dimensions and this number is called the nullity (J N ) of a ij . The problem of balancing a chemical equation then becomes the problem of determining the J N -dimensional null space of the composition matrix.

### Rank–nullity theorem

**meansrank-nullity**

In other words, the rank (J R ) of the composition matrix is generally less than its number of columns (J). By the rank-nullity theorem, the null space of a ij will have J-J R dimensions and this number is called the nullity (J N ) of a ij . The problem of balancing a chemical equation then becomes the problem of determining the J N -dimensional null space of the composition matrix.

### Electrolyte

**electrolyteselectrolyticionic solution**

An ionic equation is a chemical equation in which electrolytes are written as dissociated ions.