Bulk and surface properties of matter including nanoparticles

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レッスンノート

Particle Size Categories

Particles are grouped by diameter into coarse particles, fine particles, and nanoparticles.
Coarse particles (also called particulate matter or dust) have diameters between 1 × 10⁻⁵ m and 2.5 × 10⁻⁶ m.
Fine particles have diameters between 100 and 2500 nm (1 × 10⁻⁷ m to 2.5 × 10⁻⁶ m).
Nanoparticles are between 1 and 100 nm in size and usually contain only a few hundred atoms.
Atoms and simple molecules are around 100 times smaller than nanoparticles.
The terms PM2.5 and PM10 describe fine and coarse particles respectively, based on size in micrometres.

Scale

Nanoparticles and Nanoscience

Nanoscience is the study of structures that are 1–100 nm in size.
Research into the production and application of nanoparticles is called nanotechnology.
Nanoparticles are much smaller than fine particles, which are themselves smaller than coarse particles.
A nanometre is 1 × 10⁻⁹ m (0.000 000 001 m).
A micrometre is 1 × 10⁻⁶ m.
Nanoparticles may have different properties from the same material in bulk form.

Tio2

Surface Area to Volume Ratio

Nanoparticles have a very high surface area to volume ratio.
As particles decrease in size, their surface area increases in relation to their volume.
As the side of a cube decreases by a factor of 10, the surface area to volume ratio increases by a factor of 10.
This high ratio is why nanoparticles may have different properties from the same material in bulk form.
It also means that smaller quantities of nanoparticles are needed to be effective compared to materials with larger particle sizes.
The surface area to volume ratio is important in catalysis and surface chemistry: the higher the ratio, the more surface area is available for reaction, so the better the catalyst.

Ratio

Uses of Nanoparticles

The main industrial application of nanoparticles is in catalysis due to their high surface area to volume ratios.
Titanium dioxide in nanoparticle form is used in sunscreens as it blocks UV light but leaves no white marks on the skin.
The same chemical in bulk form is used as a white pigment in paints.
Fullerenes (nanoparticles made of carbon) are used in medicine and drug design as they are more easily absorbed and can deliver drugs to target areas more effectively.
Fullerenes are also used in electronic circuitry and as coatings for artificial limbs and joints.
Silver nanoparticles are sprayed onto fibres of medical clothing and surgical masks, giving the flexibility of a material with the added benefit of the antibacterial properties of silver.
Silver nanoparticle coated clothing can act as a built-in deodorant.

Sunscreen

Advantages and Disadvantages of Nanoparticles

Nanoparticles have widespread uses and applications that can provide an immense advance in materials technology.
The use of nanoparticles is in its early stages, so there are still many unknown factors and potential risks.
There is a lack of understanding about how nanoparticles may affect health.
Although there have been no serious short-term side effects, there could be long-term side effects not yet detected because they haven't been in use long enough.
Even a small amount of toxicity in a nanoparticle would be multiplied due to the high surface area to volume ratio.
Nanoparticles are not easily disposed of by the body, which is a cause for caution in medical applications.

Risks

Ceramics, Polymers, Composites and Metals

Glass ceramics are transparent, strong, and insulate against heat; they are more durable than other materials, making them suitable for windows.
Soda-lime glass is made by heating a mixture of limestone, sand, and sodium carbonate until it melts, then cooling it.
Borosilicate glass is made using sand and boron trioxide and has a higher melting point than soda-lime glass.
Clay ceramics are hardened materials that resist compressive forces; clay hardens at high temperatures and when fired produces a very strong and hard material.
Polymers can be tailor-designed to have specific properties, can be opaque or transparent, are usually tough and flexible, and are poor conductors of heat and electricity.
Composites are made from two components: a reinforcement and a matrix; the matrix binds the reinforcement together.
Common composites include fibreglass and steel reinforced concrete; their properties depend on the reinforcement and matrix used, so they can be tailor-engineered.
Metals are shiny, malleable, and ductile, can be mixed to form alloys, and are good conductors of heat and electricity.

Materials

Effective Use of Materials

Glass and steel are extremely useful building materials due to their high strength and durability.
Glass is transparent, hard, and has high compressive strength, making it ideal for walls and windows.
Metals are used in electrical cabling and electronics because they conduct electricity; copper is commonly used as it is a good conductor and very malleable.
Aluminium is strong but light, giving it a high strength-to-weight ratio, making it ideal for airplanes.
Steel reinforced concrete has immense tensile and compressive strength, allowing it to be used as columns and supporting structures.
Carbon-fibre composites are extremely strong and low weight, used in aviation, aeronautics, and professional racing bicycles.
Polymers are poor conductors of heat and electricity, making them good thermal and electrical insulators; they are used to insulate electrical wiring to prevent shocks and overheating.
The low melting points and flexibility of polymers enable them to be moulded into many shapes.

Materials

Key Terminology and Calculations

Nanoparticle: a particle between 1 and 100 nm in size.
Coarse particle: a particle with a diameter between 1 × 10⁻⁵ m and 2.5 × 10⁻⁶ m.
Fine particle: a particle with a diameter between 100 and 2500 nm.
Surface area to volume ratio: the amount of surface area per unit volume; it increases as particle size decreases.
Nanoscience: the study of structures that are 1–100 nm in size.
Catalyst: a substance that increases the rate of a reaction without being used up.
Order of magnitude: a rough estimate of size, often to the nearest power of ten.
You should be able to calculate surface areas and volumes of cubes, and make order of magnitude calculations.

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練習問題

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1.Place the following particles in order of size, starting with the smallest.
Easy
- Coarse particles
- Nanoparticles
- Fine particles
2.What is the approximate size range of nanoparticles?
Easy
- A1–100 nm
- B100–2500 nm
- C2500–10,000 nm
- D1–100 μm
3.Particle X has a diameter of 2.5 × 10⁻⁷ m. Which category is it most likely to belong to?
Easy
- ACoarse particles
- BFine particles
- CNanoparticles
- DAtoms
4.Why are nanoparticles effective catalysts even when only a very small quantity is used?
Easy
- AThey are reactive compounds
- BThey have a high surface area to volume ratio
- CThey have a low boiling point
- DThey can adopt different shapes
5.Nanoparticles usually contain only a few hundred atoms.
Easy
True or false?
6.As the side of a cube decreases by a factor of 10, its surface area to volume ratio decreases by a factor of 10.
Easy
True or false?
7.Which of the following are uses of nanoparticles? (select all that apply)
Medium
- ACatalysts
- BSunscreens
- CDrug delivery to cells
- DExtracting iron from its ore
- EDeodorants in clothing
8.Which of the following is NOT a use of nanoparticles?
Easy
- ADrug delivery to cells
- BExtracting iron from its ore
- CProducing suncreams
- DCatalysts

もっと問題

9.Draw one line from each particle to the correct size.
Medium
- Nanoparticles
- Fine particles
- Coarse particles
- 1–100 nm
- 100–2500 nm
- 1 × 10⁻⁵ m to 2.5 × 10⁻⁶ m
10.The study of structures between 1 and 100 nm in size is called nanoscience.
Easy
True or false?
11.Why are normal-sized particles less effective than nanoparticles at killing bacteria when used in socks?
Medium
- ANormal-sized particles are less reactive chemically
- BNormal-sized particles have a lower surface area to volume ratio
- CNormal-sized particles are too large to enter the fibres
- DNormal-sized particles have a higher melting point
12.Titanium dioxide in nanoparticle form is used in sunscreens, while the same chemical in bulk form is used as a white pigment in paints. Why do the two forms have different uses?
Medium
- AThey are different chemicals
- BNanoparticles have different properties due to their high surface area to volume ratio
- CBulk titanium dioxide is toxic
- DNanoparticles are too small to block UV light
13.A nanoparticle of a metal oxide is a cube with each side 82 nm. What is the volume of the nanoparticle?
Medium
- A5.51 × 10⁵ nm³
- B6.72 × 10³ nm³
- C5.51 × 10⁻⁵ nm³
- D6.72 × 10⁻³ nm³
14.A silver nanocrystal is a cube with each side 20 nm. What is its surface area to volume ratio?
Medium
- A0.3 nm⁻¹
- B3 nm⁻¹
- C0.03 nm⁻¹
- D30 nm⁻¹
15.A coarse particle has a diameter of 1 × 10⁻⁶ m and a nanoparticle has a diameter of 1.6 × 10⁻⁹ m. How many times larger is the diameter of the coarse particle than that of the nanoparticle?
Medium
- A625
- B62.5
- C6250
- D6.25
16.Some people are concerned about using nanoparticles to deliver drugs to cells. What is the main reason for this concern?
Medium
- AThe potential cost to the National Health Service
- BLimited information to patients on which treatments use nanoparticles
- CThe unknown effect of nanoparticles on long-term health
- DMoney could be spent on other areas of medicine
17.Which of the following are advantages of using nanoparticles in sun lotions? (select all that apply)
Medium
- AThey block UV light
- BThey leave no white marks on the skin
- CThey provide better coverage
- DThey are known to have no long-term health risks
- EThey are cheaper than all other ingredients
18.Even a small amount of toxicity in a nanoparticle would be multiplied because of its high surface area to volume ratio.
Easy
True or false?
19.Silver nanoparticles are added to the fibres used to make some socks. Why do they prevent unpleasant smells?
Medium
- AThey provide colour to the socks
- BThey kill bacteria
- CThey make the sock feel softer
- DThey absorb moisture
20.A nanoparticle of silver is a cube with each side 20 nm. What is its surface area?
Medium
- A2400 nm²
- B400 nm²
- C8000 nm²
- D120 nm²
21.Which statement about the surface area to volume ratio of nanoparticles is correct?
Medium
- AIt is lower than for the same material in bulk
- BIt is higher than for the same material in bulk
- CIt is the same as for the same material in bulk
- DIt depends only on the temperature
22.Nanoparticles are simply small pieces of a material with exactly the same properties as the bulk material.
Easy
True or false?
23.Which of the following correctly compares the size of a nanoparticle with a typical atom or simple molecule?
Medium
- AA nanoparticle is about 100 times larger than an atom or simple molecule
- BA nanoparticle is about 100 times smaller than an atom or simple molecule
- CA nanoparticle is the same size as an atom or simple molecule
- DA nanoparticle is about 10 times smaller than an atom or simple molecule
24.Which of the following is a use of fullerenes?
Medium
- AAs catalysts in the extraction of zinc
- BIn medicine and drug design
- CIn the test for water
- DAs a white pigment in paints
25.Which of the following is a use of silver nanoparticles?
Medium
- AIn suntan lotions
- BIn the extraction of zinc
- CIn medical clothing and surgical masks
- DIn the test for water
26.Which of the following statements about nanoparticles are correct? (select all that apply)
Medium
- AThey are between 1 and 100 nm in size
- BThey usually contain a few hundred atoms
- CThey have a low surface area to volume ratio
- DThey may have different properties from the same material in bulk
- EThey are larger than fine particles
27.Why are only a tiny amount of cerium oxide nanoparticles needed when added to diesel fuel as a catalyst?
Medium
- AThey have a high surface area to volume ratio
- BThey have a low melting point
- CThey are very reactive compounds
- DThey dissolve easily in diesel
28.Nanoparticles are not easily disposed of by the body, which is a cause for caution in medical applications.
Medium
True or false?
29.Which of the following is a coarse particle also known as?
Easy
- ADust
- BFullerene
- CNanoparticle
- DFine particle
30.Which of the following statements about the size of nanoparticles are correct? (select all that apply)
Medium
- ANanoparticles are between 1 and 100 nanometres in size
- BNanoparticles are smaller than fine particles
- CNanoparticles usually contain only a few hundred atoms
- DNanoparticles are larger than coarse particles
- ENanoparticles are the same size as atoms and simple molecules
31.Which of the following are properties of nanoparticles? (select all that apply)
Medium
- AThey have a high surface area to volume ratio
- BThey may have different properties from the same material in bulk
- CThey are always more toxic than bulk materials
- DThey can be effective catalysts in small quantities
- EThey have a low surface area to volume ratio
32.Which of the following are risks associated with the use of nanoparticles? (select all that apply)
Hard
- AThey may have long-term health effects that are not yet known
- BThey are not easily disposed of by the body
- CThey are too large to enter cells
- DA small amount of toxicity could be multiplied due to their high surface area to volume ratio
- EThey are always safe because they have been used for many years
33.Match each type of particle to its correct size range.
Medium
- Coarse particles
- Fine particles
- Nanoparticles
- 1–100 nm
- 100–2500 nm
- 1 × 10⁻⁵ m to 2.5 × 10⁻⁶ m
34.Match each nanoparticle to its use.
Medium
- Titanium dioxide nanoparticles
- Silver nanoparticles
- Fullerenes
- In sunscreens to block UV light
- In clothing to kill bacteria
- In medicine to deliver drugs
35.Match each material to its property or use.
Medium
- Glass
- Polymers
- Metals
- Transparent and strong, insulates against heat
- Poor conductor of heat and electricity
- Shiny, malleable and ductile
36.Arrange the following particles in order of increasing size (smallest first).
Medium
- Atom
- Nanoparticle
- Fine particle
- Coarse particle
37.Arrange the following steps to show how the surface area to volume ratio changes as a cube's side length decreases.
Medium
- Start with a cube of side 10 cm
- Reduce the side length by a factor of 10 to 1 cm
- The surface area to volume ratio increases by a factor of 10
- The surface area to volume ratio is now 10 times larger than before
38.Nanoparticles are smaller than fine particles.
Easy
True or false?
39.As the size of a particle decreases, its surface area to volume ratio decreases.
Medium
True or false?
40.Nanoparticles of a material always have the same properties as the bulk material.
Medium
True or false?
41.Complete the sentence about particle sizes.
Easy
Nanoparticles are much smaller than fine particles, which have diameters of between ____ and ____ nm.
42.Complete the sentence about the size of nanoparticles.
Easy
Atoms and simple molecules are around ____ times smaller than nanoparticles.
43.A nanoparticle of iron oxide is a cube of side 40 nm. Calculate the volume of the nanoparticle in nm³.
Medium
44.Complete the sentence about the size of a nano-sized particle.
Easy
The size of a nano-sized particle is ____ than normal-sized particles.
45.A nanoparticle of silver is a cube with each side 20 nm. Calculate its volume in nm³.
Medium
46.Complete the sentence about nanoscience.
Easy
Research into the production and application of nanoparticles is called ____.
47.Complete the sentence about the surface area to volume ratio.
Easy
As the side of a cube decreases by a factor of 10, the surface area to volume ratio ____ by a factor of 10.
48.A nanoparticle of silver is a cube with each side 20 nm. Calculate its surface area in nm².
Hard
49.A silver nanocrystal is a cube with each side 20 nm. Calculate its surface area to volume ratio.
Hard
50.What term describes particles with diameters between 1 and 100 nanometres?
Medium
51.What is the name for the study of structures between 1 and 100 nanometres in size?
Medium
52.Explain how a catalyst increases the rate of a reaction.
Medium
53.Explain why a smaller mass of nanoparticulate catalyst is as effective as a larger mass of the same material in coarse form.
Hard
54.Explain how a metal and nanoparticles of the same metal can have different properties.
Hard
55.Evaluate the use of nanoparticles in sunscreens, considering both benefits and risks.
Hard
56.Give two uses of nanoparticles.
Medium
57.A nanoparticle of iron oxide is a cube of side 40 nm. Calculate the volume of the nanoparticle in nm³.
Medium
- A64000 nm³
- B57600 nm³
- C76800 nm³
- D70400 nm³
58.A nanoparticle of silver is a cube with each side 20 nm. Calculate its volume in nm³.
Medium
- A8000 nm³
- B7200 nm³
- C9600 nm³
- D8800 nm³
59.A nanoparticle of silver is a cube with each side 20 nm. Calculate its surface area in nm².
Hard
- A2640 nm²
- B2160 nm²
- C2880 nm²
- D2400 nm²
60.A silver nanocrystal is a cube with each side 20 nm. Calculate its surface area to volume ratio.
Hard
- A2.3 nm⁻¹
- B0.3 nm⁻¹
- C1.3 nm⁻¹
- D-0.7 nm⁻¹

フラッシュカード

What is the size range of nanoparticles?

Nanoparticles are between 1 and 100 nanometres in size.

How many atoms do nanoparticles usually contain?

Nanoparticles usually contain only a few hundred atoms.

How does the size of an atom or simple molecule compare to a nanoparticle?

Atoms and simple molecules are around 100 times smaller than nanoparticles.

What is the diameter range of fine particles?

Fine particles have diameters between 100 and 2500 nm.

What is the diameter range of coarse particles?

Coarse particles have diameters between 1 x 10⁻⁵ m and 2.5 x 10⁻⁶ m.

What are coarse particles also known as?

Coarse particles are also called particulate matter or dust.

What do the terms PM2.5 and PM10 describe?

PM stands for Particulate Matter; the 2.5 or 10 refers to the particle size in micrometres, describing non-gaseous air pollution.

What is nanoscience?

Nanoscience is the research into the production and application of nanoparticles.

What is nanotechnology?

Nanotechnology is research into the production and application of nanoscience.

What is the key feature of nanoparticles that gives them different properties from bulk materials?

Their very high surface area to volume ratio.

What happens to the surface area to volume ratio as a cube's side decreases by a factor of 10?

The surface area to volume ratio increases by a factor of 10.

Why do nanoparticles need smaller quantities to be effective than normal-sized particles?

Because of their high surface area to volume ratio, a smaller quantity is needed to have the same effect.

Why are nanoparticles good catalysts?

Their high surface area to volume ratio means more surface area is available for reaction.

How does titanium dioxide behave differently in nanoparticle form compared to bulk form?

In nanoparticle form it is used in sunscreens as it blocks UV light but leaves no white marks on the skin; in bulk form it is used as a white pigment in paints.

What are fullerenes used for in medicine?

Fullerenes are used in medicine and drug design as they are more easily absorbed and can deliver drugs to target areas more effectively.

Give two uses of fullerenes besides medicine.

Fullerenes are used in electronic circuitry and as coatings for artificial limbs and joints.

Why are silver nanoparticles sprayed onto medical clothing and surgical masks?

Silver nanoparticles give the material the antibacterial properties of silver metal, which can act as a built-in deodorant.

What is the main disadvantage of using nanoparticles?

There is a lack of understanding of how they may affect health, with potential long-term side effects not yet detected.

Why is even a small amount of toxicity in a nanoparticle a concern?

The high surface area to volume ratio would multiply the toxicity, and nanoparticles are not easily disposed of by the body.

What is 1 nanometre in metres?

1 nanometre = 1 x 10⁻⁹ m = 0.000 000 001 m.

What is 1 micrometre in metres?

1 micrometre = 1 x 10⁻⁶ m.

How do buckyballs compare in size to a magnesium atom or water molecule?

Buckyballs contain 60 atoms so they are much larger than a magnesium atom or water molecule that only contains three atoms.

What is the main industrial application of nanoparticles?

Catalysis, due to their high surface area to volume ratios.

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