Unraveling the invisible world with chemical formulas!
A novel and exciting science book that will answer everyday questions using chemical formulas.

Chemistry is considered by many to be a difficult subject, far removed from everyday life.
What are the chemical formulas and chemical reaction equations made up of the various bonding patterns of elements?
We learned it in middle and high school, but it is often forgotten in daily life because it is complicated and difficult to understand.
However, the world we live in is overflowing with stories related to chemistry, such as chemical accidents, Nobel Prizes in chemistry, and the development of pharmaceuticals, and countless products utilizing chemistry are being developed, so chemistry has invisibly permeated our lives.
But why are most people not interested in chemistry?

The author of "I Wrote Everything Around Me as a Chemical Formula" was fascinated by the fact that invisible molecules make up the world in an orderly manner, and began to explore the world of chemistry in earnest.
This book conveys the wonders of the world of chemistry by reinterpreting the objects around us through the lens of chemical formulas.
In our everyday spaces, such as bedrooms, kitchens, and bathrooms, there are familiar objects such as food, clothes, soap, and electronic devices.
This book thoroughly explains the chemical principles of the objects around us by explaining them in chemical formulas.
Friendly characters and illustrations, such as researchers of the carbon C group, oxygen O, and hydrogen H, are used to easily and concisely convey the core of the content.
From middle and high school students learning chemistry to those who find chemistry difficult and abstract after graduation, interpretations of rich examples from everyday life will reveal new aspects of chemistry, bridging the gap between life and academia and providing the joy of learning.
While teaching students at the Department of Chemistry at Kwangwoon University, I received supervision from Professor Jang Hong-je, who runs the YouTube channel 'Chemistry Haak' to popularize chemistry, leading to more detailed and in-depth discussions.

Chemistry is like a language.
And in order to understand and handle a language well, you must understand and follow the grammar, which is the promise of that language.
Chemistry is simple if you approach it the same way.
Why is salt only used as NaCl, which is a combination of one Na and one Cl? Why does the neutralization reaction leave behind water (H2O) when an acid (H+) and a base (OH-) meet?
Once you know everything, it's made up of obvious chemical grammar.

《Everything Around Me Written as a Chemical Formula》 explains everything from familiar chemistry stories that we often hear around us to complex and difficult-to-understand content using chemical formulas.
It also introduces the grammar of chemical formulas and shows the convenience of expressing them in formulas.
Chemical formulas, a jumble of letters, numbers, symbols, and arrows that can be a headache for those unfamiliar with chemistry, are actually the simplest sentences of substances.
This book will give you a chance to recall the chemical formulas that are buried in your memory.
---From "The Supervisor's Note"

Recent studies have shown that there are several types of taste-sensing cells.
It has been discovered that sugar acts on cells called type II cells, and salt acts on cells called type III cells.
Type I cells also exist, but their ability to transmit taste to the brain has not yet been discovered.


As shown in the figure below, when sugar (sucrose) attaches to type II cells, and when salt (sodium ion (Na+)) enters type III cells, it becomes a signal, and the information is transmitted to the nerves that control taste (gustatory nerves) through electrical signals or chemicals.
That information is transmitted to the brain, and you feel the taste of 'salty' or 'sweet'.
---From "How does salt taste? ★ A little more detail! ★"

Dry ice is a solid, but it's actually a lump of CO2. CO2 is a gas at room temperature, but it solidifies when cooled.
It's like when you freeze water, it becomes ice.
However, while water becomes solid at 0 degrees Celsius, CO2 becomes solid at about minus 78 degrees Celsius.
Because things with such low temperatures are placed together, ice cream and frozen foods remain cold.


However, when left at room temperature, dry ice reverts to gaseous CO2 over time.
In the case of ice, when it melts it becomes liquid (water), but in the case of CO2, it becomes gas.
This is called 'sublimation'.


And eventually the dry ice disappears.
---From "Dry ice is a lump of CO2"

The acetic acid produced in the body is broken down again and excreted from the body.
In this way, our body undergoes a chemical reaction that converts ethanol and expels it from the body.
However, if you drink more alcohol than the enzyme can handle, ethanol or acetaldehyde remains in your body.
Acetaldehyde is the cause of so-called hangovers because it causes headaches and nausea.

---From "Why You Get a Hangover When You Drink Alcohol (C2H6O)"

The atoms that make up enzymes are mainly C, H, O, N, and S (S is the element symbol for sulfur), and are not much different from the molecules that have appeared so far.
However, compared to molecules that have appeared so far, it is very large.
For example, the mass of alcohol dehydrogenase or aldehyde dehydrogenase is over 1,000 times that of ethanol or acetaldehyde! This gives you an idea of ​​how large these molecules are.

As in the case of ADH and ALDH, there are many different types of enzymes, each with a different role.
There are many different types of enzymes in our bodies (many of which appear in this book).
Also, even for the same type of enzyme, some of the atoms that make up the enzyme are subtly different from person to person, and the degree of action also varies.
So, because the functions of ADH and ALDH differ from person to person, there are people who can tolerate alcohol well and those who can't.

---From "What is an enzyme? ★ A little more detail! ★"

Why does salting prevent food from spoiling and preserve it for a long time? The reason food spoils in the first place is because the number of microorganisms in the food increases.
And for microorganisms to reproduce and live, they need water, just like we do.
This is why food spoils easily during humid periods such as the rainy season.
Therefore, removing moisture from food becomes the key to long-term preservation.
And as mentioned before, salt (NaCl = Na+ and Cl-) has the property of attracting water (H2O) to each other.
So, it absorbs the water in the food well and prevents microorganisms from multiplying.

---From “Why does salt (NaCl) easily decompose in water?”

The main component of sugar is sucrose, the wonderful molecule that gives us the taste of sweetness.
The chemical formula of sucrose is C12H22O11.


Sucrose is a structure made up of molecules called glucose (C6H12O6) and fructose (C6H12O6).
Glucose has already appeared in 'Respiration and Photosynthesis'.
On the other hand, fructose came out first, and if you look closely at its chemical formula, it is C6H12O6, the same as glucose.
The chemical formula is the same, but the name is different.

---From "Sucrose, the wonderful molecule of sugar (C12H22O11) that gives sweetness"

Deodorizers eliminate unpleasant odors [deodorize] and spread pleasant scents [fragrance], but how do we perceive such smells or scents?

In fact, the way we perceive unpleasant or pleasant smells is also related to molecules.
Molecules that smell good or have an unpleasant odor exist in a gaseous state, and these molecules floating in the air are transmitted through our nose as fragrance or smell.
When molecules that cause us to sense smells attach to receptors (places where molecules attach) on cells in the nasal cavity, information is transmitted to the nerves that control the sense of smell through chemicals or electrical signals.
At this time, the cells that control the sense of smell are called the olfactory nerve.


There are many different types of molecules that allow us to perceive smell, and there are also many different types of receptors that these molecules bind to.
Humans sense smell through about 400 types of receptors.


Let's go back to the story of deodorant.
A molecule with a pleasant scent is pre-incorporated into the cyclodextrin.
And while it slowly releases those molecules, it also takes in molecules that have an unpleasant odor.
This way, it acts as a deodorizing air freshener by removing unpleasant odors while producing a pleasant scent.

---From "Cyclodextrin, a ring-shaped molecule ★ A little more detail! ★"

Mutants live comfortably in glucan and excrete lactic acid [actually, they also excrete acetic acid].
In addition, it also vomits out an acid called formic acid (HCO2H), but the proportion of lactic acid is high.]
The acid produced during this process causes concentrated demineralization, which causes teeth to dissolve and cavities to develop.
Before this happens, you must brush your teeth to remove the tartar (glucan + bacteria) that is stuck to your teeth.
Sticky tartar is not easily removed by brushing your teeth with water.
The best way to remove it is with physical force, and the most effective way is brushing your teeth.
Toothpaste contains abrasives (particles that effectively polish teeth) that are effective in removing sticky tartar.

---From "How do cavities form in teeth?"