# What are the substances that are on the left side of a chemical equation?

Jun 30, 2018

They are called the reactants.

#### Explanation:

In a chemical equation in the form of:

$A + B \to C + D$

$A$ and $B$ are considered reactants, which are the substances you begin with to do the reaction. Think of them like the "ingredients".

$C$ and $D$ are called the products. These are made after the reaction is complete. After you combine all the ingredients to make a product, the finished product can be considered $C$ and $D$.

Hope this helps!

Jun 30, 2018

Well, you tell us...and of course you MUST specify which side of the equation you face. Why so?

#### Explanation:

${\underbrace{A + B}}_{\text{the reactants}}$
$\rightarrow {\underbrace{C + D}}_{\text{the products}}$
(I could not get the equation onto the ONE line!) And as ALWAYS chemical reactions conserve (i) mass, i.e. the mass of $A + B$ is PRECISELY equivalent to the mass of $C + D$, and (ii) CHARGE...the charge of $A + B$ is PRECISELY equivalent to the charge of $C + D$.