Question

Fill in the blanks by selecting correct word/term given in the bracket.

In a balanced chemical equation, the atoms of elements are ___. (gained/lost/conserved)

Answer 1

Chemical equations

Chemical equations represent chemical reactions using symbols, formulas, and coefficients. It is a shorthand method used by chemists which gives the identity and state of all the reactants and products involved in the reaction.

Chemical equations that obey the law of conservation of mass are called balanced chemical equations. The law of conservation of mass states that matter can neither be created nor destroyed but can only be converted from one form to another. Therefore, in a balanced equation, the number of atoms of each element on the reactant side will be equal to that on the product side.

Example of a chemical equation

The balanced chemical equation for ammonia $\left({\mathrm{NH}}_3\right)$ formation from hydrogen $\left({\mathrm{H}}_2\right)$ and nitrogen $\left({\mathrm{N}}_2\right)$ can be given as:

$$\begin{gathered} {\mathrm{N}}_2\left(\mathrm{g}\right)+3{\mathrm{H}}_2\left(\mathrm{g}\right)\to 2{\mathrm{NH}}_3\left(\mathrm{g}\right) \\ \left(\mathrm{Nitrogen}\right)\left(\mathrm{Hydrogen}\right)\left(\mathrm{Ammonia}\right) \end{gathered}$$

From the equation, it can be seen that there are six hydrogen atoms on both the reactant side and product side. The number of nitrogen atoms on the reactant side and product side is 2. Therefore, the number of hydrogen atoms and nitrogen atoms on the reactant side is equal to that on the product side.

Therefore, in a balanced chemical equation, the atoms of elements are conserved.