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Balanced Chemical Reaction

In Chemistry there are many forms of calculations and most involve chemical equations. The law of the conservation of mass states that a chemical equation must be balanced. This ultimately means that each side of the equation must have the same number of atoms because neither atoms nor mass can be destroyed during a chemical reaction. The chemical formulas that react together, known as reactants, reside on the left side of a chemical equation, and the products of the reacting atoms can be found on the right side of the equation.

Counting the Coefficients
- Each side of the chemical equation contains coefficients that play a major role in determining how many atoms are involved in the chemical reaction. If the left side of the equation has the chemical formula 4Fe, or four iron atoms, then the right side must have four iron atoms as well in order for the equation to be balanced. The 4 in front of the chemical symbol for iron, Fe, is an example of a coefficient.
Subscripts Within the Parentheses
- Understanding the math behind counting subscripts in a chemical equation is the most difficult part of balancing chemical equations. The subscripts of a chemical formula only concern the element in which it follows. In the chemical formula for water, H2O, the 2 is a subscript for the hydrogen. This means that there are two hydrogen atoms and only one oxygen atom. This same concept applies to formulas within parentheses, which means that H2O is equal to (H2O).
Subscripts Outside of the Parentheses
- Subscripts that are found outside of the parentheses of a given chemical formula apply to all elements within the parentheses. The chemical formula, Al(NO3)3, has two sets of subscripts. The subscript 3 within the parentheses apply only to the oxygen element. However, the subscript 3 outside of the parentheses applies to both the nitrogen element and the oxygen element. When dealing with multiple subscripts, multiply the subscript on the outside by the subscripts on the inside of the parentheses. (NO3)3 then would have nine oxygen atoms and three nitrogen atoms because the one nitrogen atom in this formula has an assumed, unwritten subscript of 1.
Final Notes on Balancing Chemical Equations
- In chemical equations, coefficients may be changed or added on one side to achieve balance. However, subscripts in a chemical equation must remain the same or else balance will be unachievable. Also in chemical reactions, the different compounds are followed by abbreviations in parentheses that indicate the state of matter in which the compounds are in. These abbreviations are (s), (l), (g) and (aq), which stand for solid, liquid, gas and aqueous, respectively.

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