Скачать или смотреть Reactants vs Products in Chemical Reactions

In this video, we're taking a close look at the concept of reactants versus products in chemical reactions. We'll use a simple example involving aluminum foil and hydrochloric acid to illustrate this fundamental chemistry idea.

Al (s) + HCl (aq) → AlCl3 (aq) + H2 (g)

(For the full reaction see:    • Reaction of Aluminum and Hydrochloric acid...   (

At the beginning of a chemical reaction, we have what we call "reactants." These are the substances that are going to undergo changes. In our case, it's the aluminum foil and hydrochloric acid. Reactants are like the ingredients in a recipe, and they are what you start with before anything happens.

Now, when a chemical reaction takes place, there's an arrow involved, and this arrow signifies that something significant is occurring. It means that the reactants are undergoing a transformation, and as a result, they turn into new substances known as "products." So, during the reaction, atoms are rearranged, and new substances are formed. In our example, we will witness the creation of new chemical compounds as the aluminum foil reacts with the hydrochloric acid.

What's essential to understand is that this transformation is usually irreversible, meaning that once the reactants have turned into products, they won't naturally change back into their original form. It's like baking a cake – you can't un-bake it once it's done.

So, by the end of the reaction, there won't be any trace of the initial reactants; only the products will remain. This fundamental concept of reactants becoming products is at the heart of chemical reactions and helps us understand how substances can change and create new compounds through chemical processes.