No, marble is not considered a pure substance, because it is composed of multiple substances that are not bonded to each other.
In the article that follows, we’ll explain what a pure substance is, and why it is that marble does not apply.
Why Is Marble A Pure Substance? (Or Not?)
What Is A Pure Substance?
A pure substance scientifically is one that is made up of only one kind of building block.
That building block can be an element, or it can be a compound.
If the substance has more than one element or compound, it is not a pure substance.
Some good examples of pure substances include: tin, lead, silver, gold, copper, salt, sugar, and distilled water.
What Is Marble?
Marble is a metamorphic rock.
This means that marble started out as one kind of rock (or substance), and was changed as the result of significant heat or pressure.
They are often flat/squashed, crystalline, and have bands of various kinds of materials in them.
The chemical composition of marble is not consistent.
Depending upon where you find it, the marble might be composed of calcite, dolomite, or even serpentine.
The chemical composition also varies, but is often lime, silica, alumina, and oxides, among other substances.
Is Marble A Pure Substance?
No, marble is not a pure substance.
As you should be able to see, marble is generally made up of more than one substance, and often contains many substances.
These substances are not chemically bonded to each other.
While there might be compounds in marble, the compounds and elements in the rock are not chemically bonded to each other.
Since there is more than one element or compound in marble, it cannot be considered a pure substance.
Is Marble A Mixture?
Yes, marble is considered a mixture.
A mixture is a material composed of multiple substances, when those substances are not chemically bonded to each other.
In the case of a piece of marble, you’ll have any number of substances that were pretty much squashed together by the pressure of the Earth (and heat).
These substances might be in the same space (a solid rock), but they are not chemically or otherwise bonded to each other.
You could apply heat and pressure to the rock and take the components away from each other without having to break chemical or other kinds of bonds.
For this reason, marble is a mixture.
Is Marble A Heterogeneous Or Homogeneous Mixture?
Marble is a heterogeneous mixture.
A heterogeneous mixture is one that is not chemically or physically consistent throughout the material.
A homogeneous mixture is one that is chemically and physical consistent throughout the material.
In the case of marble, the substance was create by the forces of nature.
These substances were not measured or methodically mixed.
Instead, the different materials ended up where they were, and got pushed up and around.
The result is that marble is different depending upon where you look, as you will see patterns, lines, swirls, and bands in the stone.
If you were to test areas of the stone, you’d find that there would not be the same kinds of materials, or in the same amounts.
The appearance is different, as is the chemical composition of the pieces.
Since marble is not the same everywhere, or even in a reasonably sized sample, we call it a heterogeneous mixture.
Is Marble A Compound?
No, marble is not a compound.
A compound is formed when two or more substances form bonds to each other.
These substances can be elements, molecules, or other compounds.
Melting two or more substances together does not form “bonds” though the substances will be quite well mixed and stuck together once the melted materials re-solidify.
In the case of marble, the substances are mixed together by heat and pressure.
But the heat and pressure does not cause bonds to form between the elements and compounds.
Because there are no bonds between the substances (though marble contains compounds), marble itself is not a compound.
Is Marble An Element?
No, marble is not an element.
An element is a substance that cannot be broken apart into simpler substances.
In most cases, marble contains multiple substances, sometimes even at the level that humans using the stone don’t even realize.
Since marble can be broken down or apart into simpler substances, it is not considered an element.