balanced equation
When the quantity of each individual element is equal on both sides of the equation.
Examples of balanced equation in the following topics:

Amount of Reactants and Products
 Chemical equations are symbolic representations of chemical reactions.
 Therefore, in a balanced equation each side of the chemical equation must have the same quantity of each element.
 The relationship between the products and reactants in a balanced chemical equation is very important in understanding the nature of the reaction.
 A chemical equation shows what reactants are needed to make specific products.
 So the left side of the equation, $2\text{H}_2 + \text{O}_2$, has four hydrogen atoms and two oxygen atoms, as does the right side of the equation, $2\text{H}_2\text{O}$.

Balancing Redox Equations
 Notice that this equation is balanced in both mass and charge: we have one atom of iron on each side of the equation (mass is balanced), and the net charge on each side of the equation is equal to zero (charge is balanced).
 Add the two equations to cancel out the electrons to balance the equation.
 We need to balance this equation by mass.
 The equation is now balanced in mass, but not charge.
 The equation is now balanced for mass, and we need only balance for charge.

Balancing Redox Equations
 The equation should be balanced.
 The equation should be balanced.
 The equation should be balanced.
 It consists of four steps that, if followed, can balance any redox equation.
 Produce a balanced redox equation from an unbalanced one in either acidic or basic media

Reaction Stoichiometry
 In order to make any stoichiometric determinations, however, we must first look to a balanced chemical equation.
 Before performing any stoichiometric calculation, we must first have a balanced chemical equation.
 As it is written here, we should notice that our equation is not balanced, because we have two oxygen atoms on the left side of the equation, but only one on the right.
 To finish balancing the equation, we must add a coefficient of 2 in front of hydrogen gas:
 In our balanced chemical equation, the coefficient for H2(g) is 1, and the coefficient for HCl(g) is 2.

Molar Ratios
 Because the law of conservation of mass dictates that the quantity of each element must remain unchanged over the course of a chemical reaction, each side of a balanced chemical equation must have the same quantity of each particular element.
 In a balanced chemical equation, the coefficients can be used to determine the relative amount of molecules, formula units, or moles of compounds that participate in the reaction.
 The coefficients in a balanced equation can be used as molar ratios, which can act as conversion factors to relate the reactants to the products.
 For example, look at this equation:
 Calculate the molar ratio between two substances given their balanced reaction

Balancing Nuclear Equations
 To balance a nuclear equation, the mass number and atomic numbers of all particles on either side of the arrow must be equal.
 Nuclear reactions may be shown in a form similar to chemical equations, for which invariant mass, which is the mass not considering the mass defect, must balance for each side of the equation.
 To balance the equation above for mass, charge, and mass number, the second nucleus on the right side must have atomic number 2 and mass number 4; it is therefore also helium4.
 The complete equation therefore reads:
 In balancing a nuclear equation, it is important to remember that the sum of all the mass numbers and atomic numbers, given on the upper left and lower left side of the element symbol, respectively, must be equal for both sides of the equation.

MoletoMole Conversions
 Moletomole conversions can be facilitated by using conversion factors found in the balanced equation for the reaction of interest.
 To do this correctly, the reaction needs to be balanced.
 Therefore, a chemical equation is balanced when the number of each element in the equation is the same on both the left and right sides of the equation.
 Therefore, each reaction must be balanced before starting calculations.
 The chemical equation is $O_2 + 2\:H_2 \rightarrow 2\:H_2O$.

Balancing Chemical Equations
 A properly balanced chemical equation shows this.
 Therefore, to balance this reaction, a coefficient will have to be added to the NaCl on the product's side.
 Never attempt to balance a reaction by changing the subscripts on a molecule.
 To balance this reaction, add a 2 in front of the NaCl.
 Therefore, the reaction is balanced.

Thermochemical Equations
 Thermochemical equations are chemical equations which include the enthalpy change of the reaction, $\Delta H_{rxn}$ .
 A thermochemical equation is a balanced stoichiometric chemical equation which includes the enthalpy change.
 The equation takes the form:
 The equation takes the form:
 Therefore, all thermochemical equations must be stoichiometrically balanced.

The HendersonHasselbalch Equation
 The equation can be derived from the formula of pKa for a weak acid or buffer.
 The balanced equation for an acid dissociation is:
 After taking the log of the entire equation and rearranging it, the result is:
 The equation for the reaction is:
 Calculate the pH of a buffer system using the HendersonHasselbalch equation.