Substance | Definition | Types | Examples

Have you ever heard your parents discuss the difference between pure and polluted water? Do you have any idea what that means? We’ll go through it in further detail in this chapter! The concepts of substances will be discussed here. You’ll learn about the different types of substances and their examples in great detail. This is a fascinating notion that is also crucial in terms of the exam.

Definition: Substance

(1) The physical matter, material, or substance that makes up an organ or a body.

(2) (chemistry) A component, matter, or object with a particular chemical makeup and qualities.

(3) The most important or necessary component of something.

(4) Substance misuse, as in drugs.


The term substance is used in biology to refer to the material that makes up an organ, such as a ground substance or spongy substance.

All compounds are substances in chemistry, however, not all substances are compounds, because pure elements are chemical substances as well. Chemical compounds can take the form of a solid, a liquid, or a gas. Water, salt, sugar, and other substances are examples. Light and heat are examples of energy that are not considered chemical entities.

Types of Substances

Substances can be divided into two categories. They are as follows:

1. Pure Substance

Pure substances are those that are devoid of any kind of mixing and contain only one type of particle. Iron, aluminum, silver, and gold are examples of pure substances.

2. Mixture Substance

Mixtures are substances that contain two or more distinct particles. The salt solution, which is a combination of two components, salt and water, is an example of a mixture.

1. Pure Substance

What Is the Definition of Pure Substance?

Is this website of assistance to you? Only one type of particle, with a stable or unchanging structure, can generate pure substances. These substances are further broken down into elements and compounds. Elements are substances that can’t be broken down anymore. Even employing physical or chemical means, an element cannot be converted into a new element. Metals, nonmetals, and metalloids are commonly used. Compounds, on the other hand, are pure entities generated when two or more different elements are chemically united in a specific ratio of their atoms. Chemical procedures, on the other hand, can be used to break down complicated substances into their constituent elements. This page goes into pure substances in depth, including their classifications and features, as well as providing examples.

Types of Pure Substances

On the basis of their chemical composition, pure substances have been separated into two categories:

  1. Elements
  2. Compounds

1. Elements

Elements are pure substances with only one type of atom in their entire composition. They cannot be broken down into simpler substances by any physical or chemical processes. As a result, when gold is broken down, it still remains gold, making it a pure material and element. Metals, nonmetals, and metalloids are the three types of metals.

The following are the characteristics of elements:

  • It is a pure substance that is homogeneous in nature and consists of only one type of element. Iron, sulfur, and aluminum, for example. As a result, they’re all regarded elements.
  • They are incapable of being broken down into simpler substances by physical or chemical mechanisms like as heat, electricity, or chemical reactions with other molecules. As a result, when a piece of iron is heated, it only melts into iron.
  • The smallest unit of an element, an atom, is responsible for all of the element’s properties. Hence the atom of iron shows all the properties of the metal iron.
  • The boiling and melting points of elements are quite acute.

2. Compounds

A compound is a pure substance that is made up of two or more components that are chemically combined in a certain proportion. As a result, water is classified as a compound because it is made up of two elements: oxygen and hydrogen.

The following are the properties of the compounds:-

  • It is homogeneous in nature since it is made up of the same types of molecules.
  • The components of the molecules cannot be separated by the physical methods but it is possible to separate them through various chemical and electrochemical methods therefore the water can be separated into hydrogen and oxygen through the method of electrolysis.
  • Fixed components make up a compound.
  • The melting and boiling points of a compound are both very high.
  • A compound displays a distinctive property of its own that is not similar to the properties of its components.

How to Identify a Pure Substance

The only way to know for certain if a sample is a pure substance is to perform a chemical analysis. However, there are other clues that can help you make a determination:

Is it crystalline? Crystals are typically relatively pure compounds.

  • A pure substance is usually all one color. The exception is if the matter has unusual optical properties, such that it reflects or refracts light.
  • A pure substance has the same appearance and properties, no matter where you sample it.
  • If you magnify the matter, it should appear the same everywhere in its composition. The exception is when matter exists in multiple phases (e.g., melting ice).
  • If you can write the element symbol or chemical formula for a sample, it’s a pure substance.

Examples of Pure Substances:

1. Gold

No matter where it comes from, it has the same composition. Gold is formed up of atoms of gold. Gold does not contain any other elements or compounds.

2. Diamonds

They are only found in a few places deep within the Earth. In a diamond, all of the particles are identical.

3. Drinking water

If only hydrogen and oxygen are present in water, it is considered pure. In nature, finding pure water is challenging. Dissolved minerals can be found in even the cleanest spring water. Pure chemicals in nature tend to combine with other substances.

4. Baking soda (sodium bicarbonate)

Although baking soda has a wide range of applications, it is free of any additional chemical components in its purest form.

5. Table salt (sodium chloride)

One of the most prevalent compounds found in the home. The sodium chloride content of table salt ranges from 97 to 99 percent. The ionic crystal solid sodium chloride is pure sodium chloride.

6. Hydrogen gas

7. Sugar (sucrose)

8. Ammonia

9. Copper wire

10. Silicon chip

11. Copper sulfate

12. Ethanol (pure grain alcohol)

13. Tin

14. Sulfur

15. Crystals

16. Helium

17. Iron

18. Brass

19. Bronze

20. Steel

21. Saline solution

22. Vinyl

2. Mixture Substances

What is the definition of a mixture?

A mixture is a material made up of two or more separate components that have been physically mixed. A combination may typically be broken down into its constituent parts. Mixtures are another term for impure things.

Chemical compounds are not the same as mixtures because:

Physical processes such as filtration and distillation can be used to separate the constituents of a mixture.

Compounds have a set and distinct makeup, whereas mixtures have a changing composition.

Types of Mixtures:

1. Homogenous mixtures

Homogeneous mixtures are the most common type of mixture. Simply put, any mixture has a consistent composition throughout. A homogeneous mixture is one in which the composition is uniform and all of the components of the solution have the same qualities. Blood plasma is an example of a homogenous mixture in the human body. This is a colorless liquid that suspends the blood cells. It accounts for almost half of the volume of human blood. The air we breathe is a uniform mixture of oxygen, nitrogen, argon, and carbon dioxide, with minor amounts of additional components. Because the density of each layer of the Earth’s atmosphere varies, each layer of air is a separate homogeneous mixture.

2. Alloy blends

These are strong metals that make up some of the most important mixes. These unusual metals are made up of two metals that have been mixed to make them stronger. Brass, for example, is made up of zinc and copper. Stainless steel is a chromium and nickel alloy.

3. Common mixtures

When flour, sugar, butter, and milk are put together, it makes a sweet cake. You may make a freshly brewed beverage by combining coffee and water. Other typical environmental mixes are smoke and fog, which produces fog. Ocean water is a combination of salt and water. Even the air we breathe is made up of a combination of oxygen, nitrogen, and other gases.

The following are some examples of mixtures:

1. Crude oil

Crude oil is a mixture of organic components, primarily hydrocarbons, that has been refined.

2. Air

Air is a mixture of gases such as nitrogen, oxygen, carbon dioxide, neon, and others.

3. Gunpowder

Gunpowder is a mixture of potassium nitrate, sulfur, and carbon

4. Ink

Ink is a colored dye mixture that may be separated via chromatography.

5. Blood

A mixture of numerous abundant substances including red and white blood cells; plasma, containing glucose, water, albumin, and so on

6. Mineral oils

Mineral oils are a mixture of heavy alkanes that are branched, straight-chained, and cyclic.

7. Soda

Soda is a concoction of sugar, water, and flavorings.

8. Rocks

9. Muddy water

10. Sand in water

11. Salt in water

12. Mixture of sand and salt

13. Concrete

14. Automobile

15. Sterling silver (an alloy of silver and copper)

16. Honey

17. Vegetable oil

18. Rubbing alcohol

Characteristics of Mixtures

Mixtures have fewer properties, such as the mixture is an impure substance. It doesn’t have a formula. Any ratio can be fixed in a mixture. There are two types of mixtures: homogeneous and heterogeneous. Physical procedures can easily separate their constituents.

What is a toxic substance?

A toxic substance is one that has the potential to be dangerous or have negative health effects. People are often concerned about substances discovered in hazardous waste sites, such as polychlorinated biphenyls (PCBs) and dioxin. Household cleansers, prescription and over-the-counter medications, gasoline, alcohol, insecticides, motor oil, and cosmetics are just a few examples of harmful products. Under certain circumstances, every chemical can be hazardous or dangerous.

Health effects: toxic or hazardous?

Toxic chemicals are those that can harm us when they enter or come into touch with our bodies. Your health may be harmed if you are exposed to a harmful material such as gasoline. It is harmful to drink gasoline since it can induce burns, vomiting, diarrhea, and, in very large doses, sleepiness or death. Because of their physical qualities, some chemicals are dangerous: they can readily explode, burn, or react with other compounds. Gasoline is dangerous because it can burn and its vapors can explode. A chemical can be toxic, hazardous, or both at the same time.

How Can Toxic Substances Cause Harm?

Toxic substances can cause harm in a variety of ways. Because chemicals can be hazardous, it’s crucial to know how they affect your health. To evaluate the danger of detrimental health impacts from a chemical, you must first know how poisonous it is, how much and by what means a person is exposed to it, and how sensitive that person is to it.


Some compounds have a higher toxicity level than others. A substance’s toxicity is determined by the types of effects it produces as well as its potency.

Types of Effects:

  • Different chemicals have various effects. Chemical A, for example, may produce vomiting but not cancer. Chemical B may have no symptoms when first exposed, but it can cause cancer years later.


  • The potency (strong) of a substance is a measure of its toxicity. A more dangerous chemical is one that has a higher potency. Sodium cyanide, for example, is more lethal than sodium chloride (table salt), because even a small amount of cyanide can kill you.
  • The breakdown of a chemical in the human body can impact its efficacy and, as a result, its toxicity. When a toxin is absorbed into the body, its chemical structure may be altered or converted into a more or less dangerous compound. For example, the body converts carbon tetrachloride, a common solvent, into a more toxic compound that damages the liver. Other chemicals are transformed by metabolism into a form that is more easily removed by the body.


  • Only when a chemical comes into contact with or enters the body can it cause health problems.

Routes of Exposure:

  • Exposure to a drug can happen through inhalation, ingestion, or direct touch.
  • A typical method of exposure is inhalation (breathing) of gases, vapors, dust, or mists. Chemicals can enter the nose, airways, and lungs, causing irritation. They can accumulate in the airways or be taken into the bloodstream through the lungs. These compounds can then be carried to the rest of the body by the blood.
  • Another method of exposure is through the ingestion (swallowing) of food, drink, or other substances. Chemicals can be swallowed if they enter into or on food, cigarettes, utensils, or hands. Because they frequently put their fingers or other objects in their mouths, children are more likely to consume chemicals contained in dust or soil. A good example is lead in paint chips. Substances can enter the bloodstream and then be carried throughout the body.
  • Exposure can also occur by direct contact (touching) with the skin or eyes. Some chemicals are absorbed into the bloodstream through the skin. Substances will be able to enter the body more easily if the skin is broken, cut, or cracked.
  • Whether or not a harmful substance has an effect depends on the route of exposure. Lead can be toxic if inhaled or swallowed, but it is not harmful when touched because it is not absorbed through the skin.


  • A dose is the amount of a chemical that enters or contacts a person. Body weight is an important factor to consider when determining a dose. If a child and an adult are both exposed to the same amount of toxins, the child (who weighs less) may be more affected than the adult. Because an adult dose is too enormous for a child’s body weight, children are given lesser doses of aspirin than adults.
  • The more a person is exposed to a chemical, the more likely it is that health problems may arise. A relatively safe material in large quantities can be hazardous. Two aspirin tablets, for example, can help relieve a headache, but swallowing the full bottle can result in stomach pain, nausea, vomiting, headache, convulsions, or death.

Exposure medium:

  • When we breathe, eat, or touch soil, water, food, or air that includes chemicals, we are exposed to chemicals. The concentration of a chemical in a medium refers to how much of it there is. Parts per million, milligrams per liter, and milligrams per cubic meter are all common ways to report concentrations. The New York State Department of Health’s Glossary of Environmental Health Terms defines these and other units of measurement.
  • A person’s dose is calculated by multiplying the chemical’s concentration by the amount of water, air, food, or soil that he or she consumes. The normal adult, for example, drinks approximately 2 liters (nearly quarts) of water per day and breathes approximately 20 cubic meters (roughly cubic yards) of air. If a person consumes 1 milligram of lead per liter of water, he or she will consume 2 milligrams of lead every day.

Length of exposure:

  • Acute exposure is defined as a brief period of exposure. Chronic exposure refers to long-term exposure. Both may have immediate or delayed health consequences.
  • Acute exposure occurs when a person comes into touch with a chemical for a short period of time. It could be a few seconds or several hours long. Cleaning windows using ammonia, using nail polish remover, or spraying a can of paint, for example, could take a few minutes. Acute exposures include the vapors that someone might inhale while participating in these activities.
  • Chronic exposure occurs when a person is exposed to a harmful material repeatedly over a lengthy period of time (months or years). When a chemical is utilized on the workplace every day, the exposure is chronic. Some chemicals, such as PCBs and lead, can accumulate in the body over time and have long-term health consequences. At home, chronic exposures might also occur. Some chemicals included in furniture, carpeting, and cleansers can cause long-term exposure.
  • Chemicals spilling from landfills (dump sites) can poison surrounding wells or seep into basements, contaminating groundwater. People may be exposed to pollutants from their drinking water or indoor air for a long time if no precautions are taken.

Example of Toxic Substances

1. Methylene chloride

Methylene chloride is a colorless solvent with a sweet odor. When exposed to this chemical, it can injure your central nervous system and irritate your eyes and skin. Methylene chloride can cause headaches, nausea, dizziness, and sleepiness right away. These symptoms have a significant impact on your ability to coordinate. Methylene chloride poisoning can be fatal in high doses.

2. Hydrogen peroxide

Hydrogen peroxide is a highly hazardous oxidizing agent. It’s a poisonous compound that’s commonly employed as a bleaching agent, antiseptic, and oxidizer. Inhaling hydrogen peroxide vapours can cause serious lung inflammation. It can cause vomiting, stomach pains, and gastric distension if consumed. When this substance is consumed in excessive doses, it can be fatal.

3. Sodium Azide

Sodium Azide is a poisonous compound that acts quickly and is often employed as a chemical preservative in laboratories and hospitals. This chemical is a skin irritant that can cause low blood pressure, migraines, and heart failure, among other health problems. It is lethal if sodium azide is ingested, breathed, or comes into touch with the skin.

How Do We Learn How Chemicals Affect Health?

We don’t know all of the consequences of chemical exposure. Human exposures and animal research teach us about the health impacts of various substances.

Human Exposures: Even if it is partial, information about human exposures that occurred at work or by accident is quite useful. It may be difficult to determine which chemical produced a health consequence if a person has been exposed to multiple substances. Furthermore, some health impacts (such as cancer) do not manifest for several years after the initial exposure, making the disease’s source difficult to pinpoint. Even if the drug that caused the health consequence is known, the precise dose that caused the result may be unknown.

When a human population has been exposed to a harmful substance (typically at work or through an environmental source), it is sometimes compared to a population that has not. If the exposed population has an increase in a particular health symptom, the symptom may be linked to the chemical exposure. These studies, on the other hand, are frequently unable to pinpoint the particular cause of a health consequence.

Animal Studies: Animals are used in many toxicity tests. Even though animals may not react in the same way that humans do, animal testing is generally an accurate indication of chemical danger in humans. When extrapolating the results of animal toxicity testing to people, many factors are taken into account. Animals, for example, are smaller, live shorter lives, and their bodies process substances differently than humans. In animal trials, large doses are utilized to see if there is any effect. These and other differences are taken into account when developing guidelines or regulations for human chemical exposure.


In general, matter can be divided into two types: pure substances and mixtures. A pure material is a type of stuff that has a consistent composition and properties throughout the sample. Physical combinations of two or more elements and/or compounds are known as mixtures. Homogeneous and heterogeneous mixtures can be distinguished. Pure substances include both elements and compounds. Compounds are compounds that include multiple types of atoms. The simplest substances are elements, which are made up of only one sort of atom.

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