how does a chemical equation relate to a chemical reaction?

Answer 1

Shows the stoichiometric quantities involved, the reactants and the products. May show the physical states and the energy exchange involved.

Answer 2

A chemical equation is the basic overview of what is taking place in the chemical reaction. It shows the starting reactants and the ending products.

Answer 3

a chemical equation describes in terms, what happens/occurrs in a chemical reaction- basically, it is a relativley shorthand way for scientists do describe a chemical reaction that takes place.
For example, In order to write a correct chemical equation, we must balance all of the atoms on the left side of the reaction with the atoms on the right side - just like you would balance an algebraic equation. For a more specific example, If you use a gas stove to cook your dinner, chances are that your stove burns natural gas, which is primarily methane. Methane (CH4) is a molecule that contains four hydrogen atoms bonded to one carbon atom. When you light the stove, you are supplying the activation energy to start the reaction of methane with oxygen in the air. During this reaction, chemical bonds break and re-form and the products that are produced are carbon dioxide and water vapor (and, of course, light and heat that you see as the flame). The unbalanced chemical equation would be written:

CH4(methane) + O2(oxygen) CO2(carbon dioxide) + H2O(water)

a scientist would use a chemical equation to describe the process by looking at the reaction atom by atom. On the left side of the equation we find one carbon atom, and one on the right.

C H4 + O2 C O2 + H2 O

^ 1 carbon ^ 1 carbon

Next we move to hydrogen: There are four hydrogen atoms on the left side of the equation, but only two on the right.

C H4 + O2 C O2 + H2 O

^ 4 hydrogen ^ 2 hydrogen

Therefore, we must balance the H atoms by adding the coefficient "2" in front of the water molecule (you can only change coefficients in a chemical equation, not subscripts). Adding this coefficient we get:

C H4 + O2 C O2 + 2H2 O

^ 4 hydrogen ^ 4 hydrogen

What this equation now says is that two molecules of water are produced for every one molecule of methane consumed. Moving on to the oxygen atoms, we find two on the left side of the equation, but a total of four on the right side (two from the CO2 molecule and one from each of two water molecules H2O).

C H4 + O2 C O2 + 2H2 O

^ 2 oxygen ^ 4 oxygen ^

To balance the chemical equation we must add the coefficient "2" in front of the oxygen molecule on the left side of the equation, showing that two oxygen molecules are consumed for every one methane molecule that burns.

C H4 + 2O2 C O2 + 2H2 O

^ 4 oxygen ^ 4 oxygen ^

Dalton's law of definite proportions holds true for all chemical reactions. In essence, this law states that a chemical reaction always proceeds according to the ratio defined by the balanced chemical equation. Thus, you can interpret the balanced methane equation above as reading, "one part methane reacts with two parts oxygen to produce one part carbon dioxide and two parts water." This ratio always remains the same. For example, if we start with two parts methane, then we will consume four parts O2 and generate two parts CO2 and four parts H2O. If we start with excess of any of the reactants (e.g., five parts oxygen when only one part methane is available), the excess reactant will not be consumed:

C H4 + 5O2 C O2 + 2H2 O + 3O2

Excess reactants will not be consumed.

Answer 4

The equation is the description of the amounts of reactants and what they become (the products) after the reaction.
Its basically like a before and after of the reaction.
Hope this helps!