How big is a mole? (Not the animal, the other one.) - Daniel Dulek

TED-Ed
11 Sept 201204:32
EducationalLearning
32 Likes 10 Comments

TLDRThis engaging video explains the concept of the mole in chemistry, a unit used to count extremely small particles like atoms and molecules. It introduces Avogadro's number (6.02 x 10^23), named after Lorenzo Avogadro, who first proposed the idea. The script illustrates the vastness of this number with fun analogies, such as covering the Earth with a mole of donuts or creating a planet with a mole of basketballs. It concludes by comparing the mole to familiar quantities like a dozen or a pound, making the abstract concept more relatable.

Takeaways
  • 🐭 The term 'mole' in chemistry is not related to the small furry animal but is a unit for counting molecules or atoms.
  • 🌌 Moles help scientists to quantify the vast number of atoms or molecules in the universe, our bodies, or even a grain of sand.
  • 🧪 In 1811, Amedeo Avogadro proposed that equal volumes of gases at the same temperature and pressure contain an equal number of particles, a concept that was later proven correct.
  • 🔬 Avogadro's hypothesis was initially considered hypothetical and was not widely accepted by the scientific community.
  • 🗝️ Avogadro's work became foundational for atomic theory after his death when it was proven correct in the late 1860s.
  • 🔢 Avogadro's number, 6.02 x 10^23, represents the number of particles in a mole and is named after him for his pivotal idea.
  • 🍩 A mole is a massive quantity, as illustrated by the analogy of a mole of donuts covering the earth to a depth of about five miles.
  • 🏀 Another analogy is a mole of basketballs, which if stacked, could create a new planet the size of the earth.
  • 💰 The concept of a mole is similar to everyday quantities like a dozen or a ream, but it represents 602 sextillion units.
  • 🛒 Chemists use moles as a unit of measurement, akin to how we use pounds or dozens in everyday life for purchasing items.
  • 📚 The script provides a humorous and educational explanation of the concept of a mole, Avogadro's number, and their relevance in chemistry.
Q & A
  • What is the primary concept of a mole in chemistry?

    -In chemistry, a mole is a unit used to count molecules, atoms, or any extremely small entities, making it easier to deal with the vast numbers of particles involved.

  • Why was it difficult for scientists to count atoms in the early 19th century?

    -It was difficult because atoms are extremely small and there was no clear distinction between atoms and molecules. Additionally, the concept of the atom was not widely accepted at the time.

  • Who proposed the idea that equal volumes of gases, at the same temperature and pressure, contain an equal number of particles?

    -Lorenzo Romano Amedeo Carlo Avogadro proposed this idea in 1811.

  • Why was Avogadro's hypothesis initially not accepted by most scientists?

    -Most scientists did not accept the idea of the atom, and there was no way to prove Avogadro's hypothesis was correct, so they considered his work purely hypothetical.

  • When was Avogadro's hypothesis finally proven correct?

    -Avogadro's hypothesis was proven correct by the late 1860s.

  • What is the significance of Avogadro's number in chemistry?

    -Avogadro's number, which is 6.02 times 10 to the 23rd, represents the number of particles in one mole of a substance, and it is fundamental in relating the macroscopic quantities to the microscopic entities in chemistry.

  • How many gas particles are there in a balloon at zero degrees Celsius and one atmosphere of pressure?

    -There are precisely 602 sextillion gas particles, or 6.02 times 10 to the 23rd particles, in the balloon.

  • What is the molar quantity of water if you have 18.01 grams of water?

    -Having 18.01 grams of water is equivalent to one mole of water, which contains 602 sextillion water molecules.

  • How can the concept of a mole be visualized with an everyday example?

    -An everyday example would be to imagine a mole of donuts covering the entire earth to a depth of about five miles, or a mole of basketballs creating a new planet the size of earth.

  • How does the concept of a mole compare to other familiar quantities like a dozen or a ream?

    -Just as a dozen represents 12 items, a ream represents 500 sheets of paper, a mole represents 6.02 times 10 to the 23rd particles, making it a standardized way for chemists to measure large quantities of atoms or molecules.

  • What is the practical application of moles in everyday life, analogous to buying groceries?

    -The practical application of moles is similar to buying items by weight or count in a grocery store, where chemists use moles to measure and work with large quantities of atoms or molecules in a standardized way.

Outlines
00:00
🧪 Chemistry's Mole Concept

The video introduces the concept of a mole in chemistry, which is a unit used to count extremely small entities like molecules and atoms. It clarifies that a mole is not related to the small animal or skin growth commonly referred to by the same name. The mole is based on Avogadro's hypothesis from 1811, which stated that equal volumes of gases, at the same temperature and pressure, contain an equal number of particles. Initially, this idea was not widely accepted, but by the late 1860s, Avogadro's theory was proven correct and became foundational to atomic theory. The video provides an example that 18.01 grams of water, which is equivalent to 18.01 milliliters, contains Avogadro's number of molecules, which is 6.02 x 10^23. This number is so large that it's difficult to visualize, and the video humorously illustrates this by comparing a mole of donuts covering the earth to a depth of five miles or a mole of basketballs forming a new planet the size of the earth.

Mindmap
Keywords
💡mole
In the context of the video, 'mole' refers to a fundamental unit in chemistry used to express amounts of a chemical substance, specifically Avogadro's number of particles—6.02 x 10^23. It is central to the theme as it helps to quantify the vast number of atoms, molecules, or other entities in a sample. For instance, the video mentions a mole of water molecules in 18.01 grams of water.
💡Avogadro's number
Avogadro's number is a constant that represents the number of constituent particles, usually atoms or molecules, in one mole of a substance, which is 6.02 x 10^23. Named after the scientist Avogadro, it is a cornerstone of the video's narrative, illustrating the scale at which chemists work and the immense number of particles that constitute everyday substances.
💡Lorenzo Romano Amedeo Carlo Avogadro
Lorenzo Romano Amedeo Carlo Avogadro was an Italian scientist who is credited with the hypothesis that equal volumes of gases, at the same temperature and pressure, contain an equal number of particles. His work, initially not widely accepted, later became the foundation of atomic theory. The video uses his name to introduce the concept of Avogadro's number and to highlight the historical development of chemistry.
💡atomic theory
Atomic theory is the scientific theory that explains the nature of matter, stating that all matter is composed of atoms, which are the smallest units of elements. The video mentions that Avogadro's work helped lay the foundation for this theory, emphasizing the importance of his hypothesis in understanding the composition of matter.
💡gas particles
Gas particles refer to the individual molecules or atoms that make up a gas. The video uses the example of a balloon filled with gas at zero degrees Celsius and one atmosphere of pressure to illustrate the concept of a mole, stating that it contains 602 sextillion gas particles.
💡molar quantity
A molar quantity is a measure of the amount of a substance that contains Avogadro's number of particles. The video explains that chemists use moles to refer to quantities at this magnitude, allowing them to work with manageable numbers when dealing with extremely small entities like atoms and molecules.
💡donut analogy
The donut analogy is a humorous way the video uses to help visualize the vastness of a mole. It suggests that if one were to exchange water particles for donuts, a mole of donuts would cover the entire Earth to a depth of about five miles, providing a tangible, albeit夸张, image of the scale of a mole.
💡basketball analogy
The basketball analogy is another imaginative example provided in the video to illustrate the magnitude of a mole. It states that if one had a mole of basketballs, it would be enough to create a new planet the size of Earth, further emphasizing the immense scale of quantities chemists deal with.
💡penny analogy
The penny analogy is used in the video to convey the concept of a mole in terms of money. It suggests that if one received a mole of pennies on the day they were born and spent a million dollars every second until they died at 100, they would still have more than 99.99% of their money left, illustrating the almost unfathomable scale of a mole.
💡chemical quantities
Chemical quantities are units used to measure amounts of substances in chemistry. The video compares the mole to familiar quantities like pounds, dozens, and reams, explaining that just as these are used in everyday life to measure tangible goods, moles are used by chemists to measure the amount of substances in a chemical context.
Highlights

A mole in chemistry is a concept used to count molecules and atoms.

Lorenzo Romano Amedeo Carlo Avogadro hypothesized that equal volumes of gases at the same temperature and pressure contain an equal number of particles.

Avogadro's hypothesis was initially not accepted by most scientists and was considered purely hypothetical.

Avogadro's work was proven correct by 1860, laying the foundation for atomic theory, although he had passed away in 1856.

The number of particles in small samples is tremendous, with 602 sextillion gas particles in a balloon at 0°C and 1 atmosphere.

The number 6.02 times 10 to the 23rd, representing the number of particles in a mole, is named Avogadro's number.

A mole is a unit in chemistry that represents a molar quantity of 602 sextillion particles.

Moles are difficult for students to understand due to the sheer size of 602 sextillion.

18.01 grams of water, which is 18.01 milliliters, contains a mole of water molecules.

A mole of donuts would cover the entire earth to a depth of about five miles.

A mole of basketballs would be enough to create a new planet the size of earth.

Receiving a mole of pennies at birth and spending a million dollars a second would still leave over 99.99% of the money in the bank by age 100.

Chemists use moles in a similar way to how we use pounds to buy groceries.

A dozen, pair, baker's dozen, gross, and ream are familiar quantities, similar to a mole in chemistry.

The mole is a fundamental concept in chemistry for measuring large quantities of atoms and molecules.

Transcripts
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