No, vinegar is not a pure substance. It contains water and acetic acids, means it cannot be a pure substance.
Confused? Read on. In this article, we’ll explain, from a chemical standpoint, what a pure substance is and why vinegar does not qualify.
Why Is Vinegar A Pure Substance? (Or Not?)
What Is A Pure Substance?
In chemistry, a pure substance is one that is made up of only one kind of building block.
That building block can be an element, as we see in materials such as gold.
That building block can also be a compound, as we in materials such as table salt (NaCl).
The key is that the substance can only be made up of the one element, or the one compound.
If you introduce any other elements or compounds, or if the substance requires the addition of other materials, it cannot be considered a pure substance.
Next, What Exactly Is Vinegar?
We often think of vinegar as an acid, or even a weak acid.
Turns out, vinegar is mostly water, close to 90%.
The rest of the material is acetic acid, plus other potential traces of elements or compounds which are left over from the fermentation process (used to make the vinegar).
Many commercially sold vinegars also contain added flavorings to make them more attractive in the culinary setting.
Why Doesn’t Vinegar Qualify?
The key component to the pure substance equation is whether or not a substance contains only one kind of element or compound in its makeup.
If it contains more than one element or compound, it is disqualified without the need for further analysis.
And sadly, this is where vinegar fails.
Vinegar is made of water (a compound composed of hydrogen and oxygen bonded to each other). It also contains acetic acid, CH₃COOH.
The water and the acetic acid molecules are not bonded to each other.
The acetic acid molecules could be removed from the water, and vice versa.
And this does not even take into account the remaining traces of other elements/substances.
Since vinegar is made up of more than one building block, it is not a pure substance.
Is Vinegar A Mixture?
Yes, we would call vinegar a mixture.
A mixture is a substance composed or more than one kind of material, where the materials are not bonded to each other though they share the same physical space.
In a mixture, you might not be able to tell that the different parts aren’t bonded. They might look completely melted, fused, or made into a whole to our naked eyes.
It is at the molecular level that makes a difference. At that level, they can still be easily separated without having to break any chemical bonds.
In the case of vinegar, you have water and acid. The acid molecules float around in the water, but are not bonded to each other.
The different kinds of molecules can be separated from each other.
For these reasons, vinegar is a mixture.
Is Vinegar A Homogeneous Or Heterogeneous Mixture?
Vinegar is considered a homogeneous mixture.
A heterogeneous mixture is a mixture that is not consistent chemically or even appearance-wise throughout the material. Depending where you same, you’ll find that it looks different from other areas, or even has a different chemical composition.
A homogeneous mixture is one that is consistent in both appearance and chemical composition, regardless of where you look or sample.
With the case of vinegar, the acid and other trace materials are generally spread out evenly throughout the material.
In most cases, when you sample one area of the vinegar, it will look and test the same as another area.
That being said, vinegar could be made into a heterogeneous mixture, especially if you were trying to add flavorings, color, or other additives to the material.
Remember, the base of this substance is water. Water will only absorb so much of a material before it comes saturated. If you attempt to put too much of a material in water, eventually the material will not dissolve, and certain areas will contain more or less of it.
But under normal circumstances, vinegar is a homogeneous mixture.
Is Cider Vinegar A Pure Substance?
No, cider vinegar (like apple cider vinegar) is not a pure substance.
As noted above, vinegar is made up of water and an acid. These materials are not bonded to each other.
Because the water and the acid (and other materials that made apple cider vinegar unique) are not bonded to each other, there is more than one substance in vinegar.
And when there is more than one substance (element or compound) in a material, it cannot be considered a pure substance.
Is Vinegar A Compound?
No, vinegar is not a compound.
A compound is formed when two separate and different materials (element, molecule, or even another compound) form a bond to each other.
In the case of vinegar, there are multiple substances in it that are not bonded to each other.
There may be compounds in vinegar, but vinegar itself is not a compound.
Interested in learning more about pure substances and mixtures? Or whether materials like water, orange juice, paper, or ammonia are considered pure substances or mixtures?
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