Main Concept

A chemical equation describes the changes that occur during a chemical reaction. The equation shows the reactants on the left hand side and the products on the right hand side of the arrow. Balancing a chemical equation is a mathematical approach used in chemistry to establish the relationship between the quantity of reactants and products.

To balance chemical equations, the following three steps are used:

In the following examples, you will be given the chemical equations and states. You are responsible for balancing them.

Examples

Questions

Type integer coefficients in front of the reactants and products to balance the chemical equations. Use the smallest integers that work. If no coefficients are required to balance the equation, simply place the integer 1 in front of each reactant and/or product.  

Click "Check" to see  whether your response below is the correct balanced chemical equation.

Solutions

Solution 1 2${\mathrm{Cu}}_{\left(s\right)}\+$$\mathbf{1} {\mathrm{O}}_{2\left(g\right)} \to$2 CuO${}_{\left(s\right)}$ Solution 2 $\mathbf{2}\mathbf{ }{\mathrm{H}}_2{\mathrm{O}}_{\left(l\right)} \to \mathbf{2}\mathbf{ }$${\mathrm{H}}_{2\left(g\right)}\+\mathbf{1}\mathbf{ }$${\mathrm{O}}_{2\left(g\right)}$ Solution 3 3 F${\mathrm{e}}_{\left(s\right)}\+\mathbf{4}\mathbf{ }$${\mathrm{H}}_2{\mathrm{O}}_{\left(g\right)} \to \mathbf{ }\mathbf{4}\mathbf{ }$${\mathrm{H}}_{2\left(g\right)}\+\mathbf{1}\mathbf{ }$${\mathrm{Fe}}_3{\mathrm{O}}_{4\left(g\right)}$ Solution 4 2 AsC${\mathrm{l}}_{3\left(\mathrm{aq}\right)}\+\mathbf{3}\mathbf{ }$${\mathrm{H}}_2{\mathrm{S}}_{\(\mathrm{aq}} \to \mathbf{1}\mathbf{ }$${\mathrm{As}}_2{\mathrm{S}}_{3\left(s\right)}\+\mathbf{6}\mathbf{ }$${\mathrm{HCl}}_{\left(\mathrm{aq}\right)}$ Solution 5 $\mathbf{1} {\mathrm{Fe}}_2{\mathrm{O}}_{3\left(s\right)}\+\mathbf{3}\mathbf{ }$${\mathrm{H}}_{2\left(g\right)} \to \mathbf{2}\mathbf{ }$${\mathrm{Fe}}_{\left(s\right)}\+\mathbf{3}\mathbf{ }$${\mathrm{H}}_2{\mathrm{O}}_{\left(l\right)}$ Solution 6 1 CaC${\mathrm{O}}_{3\left(s\right)} \to \mathbf{1}\mathbf{ }$Ca${\mathrm{O}}_{\left(s\right)}\+\mathbf{1}\mathbf{ }$C${\mathrm{O}}_{2\left(g\right)}$

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