No, concrete is not considered a pure substance. It is made up or more than one material that is not bonded chemically to the others.
In this article, we’ll explain in simple terms what a pure substance is, what concrete is, and why it is that concrete does not qualify.
Why Is Concrete A Pure Substance (Or Not)?
What Is A Pure Substance?
Chemically speaking, the concept of what a pure substance is, is not difficult.
A pure substance is made up of only one thing.
That one thing could be an element, such as silver, lead, or gold.
That one thing could be a compound, such as salt, water, or carbon dioxide.
If the substance contains more than one element or compound, and those materials are not bonded together into a new compound, the material is not a pure substance.
What Is Concrete?
To understand why concrete does not qualify as a pure substance, you have to know what concrete is.
Concrete, when you walk on it, looks like it is pretty consistently one substance.
In fact, concrete is made up of many substances, and that formula for concrete varies dramatically, depending on who makes it, and what it is being used for.
In general, concrete is made up of “fine” materials that are in granular form like sand, along with materials for the “coarse” portion like gravel.
Then, there is a glue that holds the fine components and gravel components together.
The fine components can be many different substances, such as silica, basalt, granite, or other types of unknown crushed rock.
The coarse components can also be many different substances, but we often see sandstone, limestone, and basalt.
The glue that holds the fine and coarse components together is usually asphalt or Portland cement.
Needless to say, there can be many different kinds of rocks and minerals in concrete.
Is Concrete A Pure Substance?
We hope it is pretty obvious that concrete is not a pure substance.
As noted above, a pure substance is made up of only one kind of material, either an element or a compound.
In the case of concrete, any number of elements and compounds are used in the formation of this well known building material.
There are so many, that sometimes we aren’t even necessarily sure exactly what the chemical composition of the concrete is, especially when miscellaneous crushed rock is used as the coarse component, and sand (which is made of many types of rocks and minerals) is used as the fine component.
Is Concrete A Mixture?
Yes, concrete is a mixture.
A mixture is a material made up of more than one substance, when the substances are not chemically bonded to each other.
In the case of concrete, the substances are well mixed and the material is hardened. It is not easy at all to pull the substances apart.
Being glued together is not the same as being chemically or otherwise bonded at the molecular level.
It would be possible to separate the various rocks and minerals from each other without having to break chemical bonds.
As a result, this makes concrete a mixture.
Is Concrete A Heterogeneous Or Homogeneous Mixture?
Concrete is a heterogeneous mixture.
A homogeneous mixture is one that is chemically consistent through.
A heterogeneous mixture is one that is not chemically consistent throughout.
In the case of concrete, any number of minerals can be used in the formation of a particular pieces of concrete.
The coarse aggregate may be made of one kind of rock or mineral, or many different kinds.
The same is true with the sand or fine material.
Concrete is usually mixed pretty extensively before it is poured or placed.
But that mixing does not break down the coarse pieces enough to evenly mix up and distribute all of the various substances homogeneously throughout the concrete.
Since the material is not going to be chemically consistent (and such consistency is not necessary for the performance of the product), concrete is a heterogeneous mixture.
Is Concrete A Compound?
No, concrete is not a compound.
A compound is formed when more than one substance (usually an element, molecule, or other compound) bonds to another element, molecule, or compound.
In the case of concrete, the materials are mixed up together and the material sets up, but no chemical bonds are formed between the substances.
As a result, since there are no bonds between the substances, concrete is not a compound.
Is Concrete A Rock?
No, concrete is not a rock.
A rock is an aggregate of minerals and rock mixtures. The rock might be made up of one kind of mineral, or other kinds of rock and minerals.
In the case of concrete, if you ignore how it is formed, it would seem like a rock.
After all, it is made up of many different kinds of minerals and rock mixtures.
It displays the same physical characteristics of rocks that you observe out in the world.
The difference in this case is that concrete is made by humans, while rock is made in nature.
To be considered a rock, the material must be made up of the minerals and rock material as we discussed, and it also must be naturally occurring.
Since concrete does not exist naturally, it cannot be a rock.