Over the past 20 years, acetic acid has become a highly in-demand global commodity used in the chemical and food industries, among others. With a growth projection in the billions, measurements are important for this substance, so what is the molar mass of acetic acid?
The molar mass of acetic acid is 60.06 g/mol. Molar mass enables the conversion of the tiniest particles from atomic mass into a physical mass. Most commonly associated with vinegar, acetic acid poses both health benefits and risks. While primarily manufactured through conventional pathways, sustainable green production is on the rise.
This guide will clarify what a mole means, its relation to molar mass, and its significance in chemistry. You will discover what acetic acid exactly is, and where it is applied, and why its molar mass matters. Plus, you will gain insight into both its conventional and green production pathways.
What Is Molar Mass?
To make sense of molar mass, let us start with the chemistry basics. Chemists need a tool to quantify atoms and molecules to understand their interaction.
The mole concept enables the measurement of the tiniest particles, not visible to the naked eye nor measurable on a human scale, even in large quantities.
One mole, really just a quantity of something, always contains the same number of particles and is the equivalent of 6.022 × 1023.
This number in the mole is called Avogadro’s number. We recognize by the symbol NA, and it enables chemists to bridge the atomic world with physical mass, namely grams.
Molar mass, also known as molecular weight, is the mass in grams of one mole of a substance, indicated by g/mol.
The molar mass varies depending on the substance’s make-up and therefore produces different results on an atomic, molecular, and formula level. An example will help clarify this.
To calculate a substance’s molar mass, you will need to use the periodic table of elements. The molar mass of the atom of Oxygen (O) is 16 g/mol, as the periodic table indicates.
The molar mass of the molecule O2 is 2 x 16 g/mol = 32 g/mol. The molar mass of Hydrogen (H2O) is (2 x 1,008 g/mol) + 16 g/mol = 18.02 g/mol (source).
Each element is different, and to understand molar mass for each, you need to grasp the basics of molecular structure. To learn more about oxygen, read our helpful guide, “Is Oxygen O₂ or just O: Understanding the Molecular Structure of Oxygen.”
It’s essential to note that, although the values of molar mass and molecular weight are identical, we should not confuse molar mass with molecular mass.
Molecular mass measures the mass of one molecule in atomic mass units (amu), while molar mass looks at the mass of one mole measured in g/mol (source).
What Is the Molar Mass of Acetic Acid?
If we calculate the molar mass of acetic acid using the periodic table, we will arrive at 60.06 g/mol. Let’s break down the molecular formula of acetic acid step-by-step to show you how we arrive at this.
The molecular or chemical formula of acetic acid is CH₃COOH. Let’s start by writing down the molar mass of each individual element.
- The molar mass of carbon (C) is 12.01 g/mol
- The molar mass of hydrogen (H) is 1.008 g/mol
- The molar mass of oxygen (O) is 16 g/mol
To calculate the molar mass of acetic acid, we can simply write out the full molecular formula, CH₃COOH, in g/mol. Have a look at how we have done this below.
C H₃ C O O H
12.01 + (3 x 1.008) + 12.01 + 16 + 16 + 1.008 = 60.06 g/mol
The molar mass of acetic acid is an important yardstick to conduct experiments in chemistry. It enables the conversion of atomic mass into physical mass and ensures that the accurate amount is weighed out on a scale.
Plus, it enables the detection of levels of acetic acid in substances such as vinegar. This enables government agencies such as the United States Food and Drug Administration (FDA) to monitor these levels for public health purposes.
Acetic Acid vs. Vinegar
Acetic acid is not the same as vinegar, although many use the two terms interchangeably.
Instead, vinegar is a mixture of acetic acid and water. While the percentage of acetic acid ranges per finished product and geographical location, let’s take a closer look at what acetic acid actually is.
What is Acetic Acid?
Acetic acid is an organic compound that belongs to the widely occurring carboxylic acids organic compound class. It is a colorless liquid and contains antibacterial and antifungal properties. Other names are ethanoic acid, 64-19-7, and ethylic acid (source).
You’ll often see acetic acid referred to as glacial acetic acid due to its inclination to crystalize when it is cooled. It can burn organic tissue, such as skin, and doctors use it within the medical field to remove warts.
The majority of acetic acid produced today is synthetic, the result of chemical reactions, used mainly for commercial purposes.
Our bodies also produce small amounts of acetic acid, which plays a vital role in the body’s metabolism.
Scientists have discovered it in various organs, such as liver and kidney tissues. They have also found traces in fluids such as urine, saliva, and breastmilk (source).
Lastly, acetic acid is naturally produced in substances that contain sugar and/or alcohol, such as fruits, juices, wine, and beer.
The presence of acetobacter, a species of Acetic Acid Bacteria (AAB), enables a two-step fermentation process, known as aerobic glycolysis.
During this oxidative fermentation process, natural sugars convert into alcohol and subsequently into acetic acid. This oxidative fermentation process is most commonly used in the production of vinegar (source).
Vinegar
Commonly found in most modern households, vinegar holds a long and rich history.
Recorded vinegar production dates back as far as 200 BC, and the word is derived from the French vin aigre, which translates to sour wine. We can make vinegar from almost any carbohydrate that can ferment (source).
The vinegar-making process is one of double fermentation, combining yeast and AAB.
A large variety of vinegar exists, but white vinegar is by far the most common, which is produced from alcohol distillation. Other varieties include apple cider vinegar, wine vinegar, balsamic vinegar, and rice vinegar (source).
The acetic acid within vinegar gives it its distinctive taste and odor. Most kinds of vinegar contain between four and five percent acetic acid. Too high of an acetic acid concentration produces a very bad-tasting vinegar (source).
Chemists can determine the concentration of acetic acid in vinegar through a process called titration. The term “grain strength” indicates 10 times the level of acetic acid concentration. For example, a vinegar with 4 percent acetic acid has a grain strength of 40 (source).
The medicinal use of vinegar to fight off infections and treat critical diseases dates back centuries. While still commonly used for treatments varying from ear infections to jellyfish stings and head lice, scientific evidence is not compelling (source).
The Versatile Applications of Acetic Acid
Acetic acid is a multi-application commodity that has seen exponential growth in demand over the years. Its application, both direct and indirect, can be found across industries, such as chemical, pharmaceutical, textile, cosmetics, and food.
From Chemical to Food Industry
Within the chemical industry, the most prominent usage of acetic acid is as a rubber substitute and in photographic and film chemicals. It can also be traced back to adhesives, plastics, latex paints, pesticides, insecticides, descalers, and rust removal products (source).
In the pharmaceutical industry, acetic acid can be found in antiseptic products due to its antibacterial properties.
It is generally present in a heavily diluted format, with most antiseptics containing as little as one percent of acetic acid.
Diluted acetic acid is used to treat infections in the ear canal, to clean bladders of catheter patients, and for visual inspection in cervical cancer screening (source).
In the textile industry, acetic acid is mainly used for dying purposes. In recent years, citric acid has become more present both for cost-reduction and environmental reasons, but not yet on a large industrial scale (source).
Acetic acid can be found in personal care products such as shampoos and conditioners. It can also be found in certain skincare products, as well as several types of mouthwash (source).
Apart from its presence in vinegar, acetic acid can be found as both an additive and preservative in many food products. Common pantry staples that include trace amounts of acetic acid are ketchup, dressings, mayonnaise, cheese, and sauces.
Health Risks and Benefits of Acetic Acid
Acetic acid is an extremely dangerous substance if not used in a controlled and safe environment. Exposure to these risks is greatest for those involved in the production processes of the chemical.
Aside from irritation to eyes, nose, and skin, acetic acid can cause severe damage to organs and result in life-threatening situations if one is overexposed.
Using Personal Protection Equipment (PPE) is essential when working with acetic acid in an undiluted format.
Despite the risks associated with the production process, the United States Food and Drug Administration (FDA) recognizes acetic acid as a generally safe substance in food. Along with good manufacturing practices and standards, it poses little to no risk (source).
Synthetic acetic acid did not use to traditionally occur in food products, but current legislation allows its presence in food as an additive.
While the impact of synthetic acetic acid and its by-products on health is largely unknown, a worrying trend has been the inability to trace its presence in food products.
While the FDA states that synthetic acetic acid does not pose a health risk, the limited effective rapid-test methods to detect degraded vinegar with synthetic acetic acid impacts fair trade negatively and could expose consumers to a potential array of dangers (source).
Acetic acid, predominantly in the form of apple cider vinegar, experienced a global boost in the health field during recent years.
Some of the bolder health claims regarding apple cider vinegar include drastic weight loss, controlling high blood pressure, and a cure for cancer.
While scientific evidence for sustained long-term weight loss is not convincing, there are signs that using apple cider vinegar aids blood sugar control. At the very least, it has a hand in keeping bacterial growth on your salads at a minimum (source).
Production Pathways of Acetic Acid
Due to its ever-increasing global demand, it is important to look at the manufacturing pathways of acetic acid. Acetic acid has both conventional manufacturing pathways as well as the more recent green production processes.
Conventional Manufacturing Practices
Many different conventional manufacturing practices exist, with some being chemical and others fermentative in nature.
The most common present-day efficient chemical method is known as the Cativa process. It involves the production of synthetic acetic acid through methanol carbonylation and was developed by the British Petroleum Company (BP) (source).
Other conventional chemical methods include acetaldehyde oxidation and hydrocarbon oxidation derived from petroleum stock.
Conventional fermentation processes are through wooden barrels, known as the Orleans method, the trickling process, and the continuous submerged process (source).
The conventional methods are complex, multi-layered, and capital and energy-intensive. Plus, chemical processes pose serious risks to the environment.
With soaring international demand, the calls for increased awareness of the impact of global warming on the environment have intensified in recent years, especially where it concerns green and sustainable production practices (source).
Green Production and Sustainability
A lot of new green techniques and processes have recently emerged. While applaudable, most have failed to reduce production costs and limit energy consumption.
One sustainable alternative proposes to use carbon monoxide (CO) and carbon dioxide (CO2) for the production of acetic acid (source).
While this approach certainly adheres to a green and sustainable production method of acetic acid, it battles to locate an effective catalyst due to the lack of chemical activity in carbon dioxide and methane (source).
Another promising green production method of acetic acid is membrane-based technology. This compression technology, also known as nanofiltration (NF), splits liquid depending on size and charge.
A positively charged membrane can recover organic acid and therefore offers a sustainable, low-energy, and bio-friendly solution (source).
Final Thoughts
Acetic acid is a global commodity with a remarkably versatile application across industries. Chemistry’s ability to quantify this adaptable substance through molar mass has left a significant mark on modern society.
It has led to lifesaving antiseptics, food and flavor enhancers through vinegar, and even filtered into the cosmetic field through items like hair products.
While very dangerous in an undiluted state, most diluted acetic acid found in food and other products poses little to no health risk. Health benefits, especially in the form of apple cider vinegar, are often overstated and carry little scientific proof.
The staggering demand for acetic acid has brought together a shift in manufacturing to achieve lower production costs and embrace environmentally friendly production methods. While conventional practices are still dominant, sustainable bio-friendly solutions are steadily gaining ground.