# Chemical equations

The online chemical equation simulations on this page will help you to better understand how chemical equations work and the laws that govern them.

Chemical equations are symbolic representations of chemical reactions. These equations describe the changes that occur in the atoms and molecules of substances that are combining or decomposing during a reaction.

Chemical equations are written in the form of chemical formulas that represent the substances involved in the reaction. For example, the chemical equation for the combustion of methane is:

CH4 + 2O2 → CO2 + 2H2O

In this equation, CH4 represents methane, O2 represents oxygen, CO2 represents carbon dioxide, and H2O represents water. The numbers in front of the chemical formulas are the stoichiometric coefficients, which indicate the ratio in which the substances react and are produced.

It is important to note that chemical equations must be balanced, that is, they must have the same number of atoms of each element on both sides of the equation. Balancing chemical equations is done by adjusting the stoichiometric coefficients, ensuring that the law of conservation of matter is met.

In short, , the chemical equations are an important tool for understanding how chemical reactions occur and for predicting the products of a reaction. They are also used to calculate the amount of reactants needed to produce a specific amount of product and vice versa.

## Balancing chemical equations

How do you know if a chemical equation is balanced? What can you change to balance an equation? Play a game to test your ideas!

## Reactants, products and leftovers

Create your own sandwich and then see how you can make many sandwiches with different amounts of ingredients. Do the same with chemical reactions. See how many products you can make with different amounts of reactants, products and leftovers Can you get a perfect score on each level?

## Law of Definite Proportions

In a reaction between hydrogen and oxygen to form water, two atoms of hydrogen combine with one atom of oxygen to form a water molecule. Hydrogen and oxygen always react in a 2:1 ratio to form water.