Nanochemistry - class-IX

Quantum dot is a Semi conductor made up of Nano particles.Basically a single electron trapped inside a cage of atoms and when the dot is exposed to a pulse of light at the right time and wavelength, the electron is raised to an exited state. Thus when the electron fall back to its ground state, these dots then have the ability to glow. Quantum dots are a special class of materials known as semiconductor. Quantum dots are very special because they are so small that 4,000,000 dots take up 2 cm. Hence option C is correct.

$\text{Nano wire and Nano tubes :}$

• The size and surface characteristics of nanoparticles can be easily
  manipulated. This could be used for both passive and active drug
  targeting
• Nanoparticles can be made to control and sustain release of the drug during the transportation as well as the location of the release.
  Since distribution and subsequent clearance of the drug from the body can be altered, an increase in drug therapeutic efficacy and reduction in side effects can be achieved.
• Choosing an appropriate matrix also helps in increasing the efficacy and reducing side effects
• Targeted drugs may be developed
• Various routes of administration including oral, nasal, injection, intra-ocular (within the eyes) etc. can be used.
• Hence option D is correct.

Two principal factors cause the properties of nanomaterials to differ  significantly from other materials: increased relative surface area, and
quantum effects. These factors can change or enhance properties such as
reactivity, strength and electrical characteristics.
Increased relative surface area, and quantum effects of nano particles increases the :

All are having one dimension and can extend up to other two dimensions also.

Nanomaterials have atleast one dimension between 1 nm and 100 nm.

• The size and surface characteristics of nanoparticles can be easily
  manipulated. This could be used for both passive and active drug targeting
• Nanoparticles can be made to control and sustain release of the drug during the transportation as well as the location of the release.
  Since distribution and subsequent clearance of the drug from the body
  can be altered, an increase in drug therapeutic efficacy and reduction in side effects can be achieved.
• Choosing an appropriate matrix also helps in increasing the efficacy and reducing side effects
• Targeted drugs may be developed
• Various routes of administration including oral, nasal, injection, intra-ocular (within the eyes) etc. can be used.
• Hence option D is correct.

Carbon nano tubes are made up of carbon nano particles. Example: Fullerene is the allotrope of carbon. It is also a nanomaterial. The cylindrical fullerene is called as carbon nano tube. 

Nanomaterials are not simply another step in the miniaturization of  materials or particles. They often require very different production approaches. There are several processes to create various sizes of nanomaterials, classified as top-down and bottom-up. Although large numbers of nanomaterials are currently at the laboratory stage of manufacture, many of them already are being commercialized. Hence option D is correct.

The size of a nanoparticle is  about 50000 times smaller than the diameter of a single strand of human hair and 1/100th of a typical bacterium.

All of the given statements are true. Nano materials have different colours than the bulk material. Gold nano particles are red. Bulk gold metal is yellow.

Nanoparticles are the nanomaterials with three dimension between 1 nm and 100 nm. Nanolayers are the nanomaterials with only one dimension between 1 nm and 100 nm. Nanotubes or nanowires are the nanomaterials with two dimension between 1 nm and 100 nm.

All of the given statements are true.
The nanoparticles have substantial percentage of atoms on the surface and are therefore bound less tightly than those within the bulk solid. For example, a 5 nm nanoparticle has about 30%  of the atoms on its surface. This property of nanoparticles is responsible for the lower melting point and greater reactivity of nanomaterials than the bulk solid.

1 nm is the width of 4 hydrogen atoms placed side by side.

The size of nanomaterials lies between the width of 4-25 hydrogen atoms laid side by side. 1 nm is the width of 4 hydrogen atoms placed side by side. Nanomaterials have atleast one dimension between 1 nm and 100 nm.

The nanomaterials tend to have greater reactivity than the bulk material. For example, gold nanoparticles are chemically reactive whereas bulk metal is inert.

The nano materials have lower melting points than the bulk material.

All of the given statements are correct.
When a quantum dot is irradiated with UV light, it emits visible light, the wavelength of which depends on the size of nanoparticles. For example, a 3nm cadmium selenide particle emits green light of wavelength 520 nm whereas 5.5 nm particle of the same substance emits red light at the wavelength of 620 nm.
The rainbow colours are emitted by the nanoparticles of different size of single substance.
The wavelength of light emitted decreases from red to violet in the rainbow spectrum as the size of the nanoparticles decreases.

The size of a nanoparticle is  about 50000 times smaller than the diameter of a single strand of human hair and 1/100th of a typical bacterium.

Carbon nanotubes are used as strengthening rods and toughening elements in structural composite materials. Example of a carbon nanotube is Fullerene nanotube.

All of the above are the disadvantages of nanomaterials.
Nanomaterials are very expensive.
Also, nanomaterials are also pretty difficult to manufacture
Hence, products made with nanotechnology are more expensive.
Nanoparticles are very small, inhalation of these particles can cause problems similar to the problems from inhaling minute asbestos particles.

The following lists the disadvantages of nanomaterials
The value of oil may decrease as more efficient sources of energy might be developed which won't require the use of fossil fuels.
Products at the molecular level can be developed,  so that diamonds may lose its value due to mass production.

The nanomaterials are classified into
nanolayers, nanotubes or nanowires and nanoparticles.
Nanolayers are the nanomaterials with only one dimension between 1 nm and 100 nm.
Nanotubes or nanowires are the nanomaterials with two dimension between 1 nm and 100 nm.
Nanoparticles are the nanomaterials with three dimension between 1 nm and 100 nm.

Gold nanoparticles are highly effective as selective oxidation catalysts. It is used in the oxidation of alcohols and aldehydes.

The metal oxide nanoparticles are widely used in sunscreens and cosmetics, stain-resistant fabrics and dirt repellent paints. They are used in sunscreen and cosmetics because they reflect the visible light and absorb UV light efficiently.

All of the given statements are true.
The surface of a quantum dot can be chemically modified by attaching an organic molecule. A modified quantum dot targets and forms a chemical bond with a specific biomolecule such as DNA or protein.
The modified quantum dots are thousand times smaller than the human cells. They can easily penetrate cell membranes.
When modified quantum dots bound to a bio-molecule are irradiated with UV light they emit light of a particular wavelength dependent on size of quantum dots. 
If a mixture of quantum dots of different size and different surface modifications are irradiated with a single light source, the detection tracking and having coloured images of a number of different biomolecules within a cell is possible.

In future nanomaterials can be used to detect human cancer at its earliest and most curable stages. Currently, the application of various nanoparticles (including quantum dots) for cancer detection and treatment is under study.

As a result of their good physical and chemical properties such as the strongest and stiffest materials yet discovered in terms of tensile strength and elastic modulus respectively and good electrical and thermal conductor, carbon nano tubes have potential use in a variety of industrial and biomedical applications including: Catalysis, Biosensor, Drug carriers composite materials with improved mechanical and electrical properties. Hence option D is correct

Nanoscience deals with the scientific study of objects with sizes in the 1-100 nm range in one dimension.

Accordingly, in zero-dimensional (0D) nanomaterials all the dimensions are measured within the nanoscale (no dimensions are larger than 100 nm). Most commonly, 0D nanomaterials are nanoparticles.
Hence option A is correct.

In
two-dimensional nanomaterials (2D), two dimensions are outside the
nanoscale.This class exhibits plate-like shapes and includesgraphene,
nanofilms, nanolayers, and nanocoatings.
Hencce option B is correct.

n
two-dimensional nanomaterials (2D), two dimensions are outside the
nanoscale. This class exhibits plate-like shapes and includes graphene,
nanofilms, nanolayers, and nanocoatings.
Hence option D is correct.

SA/V ratio of sugar granules is greater than sugar cube so in Sugar granules, a greater portion of sugar atoms will be on surface so contact with water will be more as compared to sugar cube and it will dissolve faster than big piece of sugar cube.

Two principal factors cause the properties of nanomaterials to differ significantly from other materials: increased relative surface area, and quantum effects. These factors can change or enhance properties such as reactivity, strength and electrical characteristics.

As a particle decreases in size, a greater proportion of atoms are found at the surface compared to those inside. For example, a particle of size 30 nm has 5% of its atoms on its surface, at 10 nm 20% of its atoms, and at 3 nm 50% of its atoms.

Thus nanoparticles have a much greater surface area per unit mass compared with larger particles. As growth and catalytic chemical reactions occur at surfaces, this means that a given mass of material in nanoparticulate form will be much more reactive than the same mass of material made up of larger particles.

In one-dimensional nanomaterials (1D), one dimension is outside the nanoscale. This class includes nanotubes, nanorods, and nanowires.
Hence option A is correct.

In
one-dimensional nanomaterials (1D), one dimension is outside the
nanoscale. This class includes nanotubes, nanorods, and nanowires.
Hence option D is correct.

Three-dimensional nanomaterials (3D) are materials that are not confined to the nanoscale in any dimension. This class can contain bulk powders, dispersions of nanoparticles, bundles of nanowires, and nanotubes as well as multi-nanolayers. Hence option A is correct.

Quantum dots are semiconductor nanoparticles that are about 1-100 nm in diameter.

                            	<span class="ng-binding">Nano science is the study of objects of particles of smaller size of 1-100 nm. Nano particles are such small sized particles. Hence, option A is correct.<br></span>

Accordingly, in zero-dimensional (0D) nanomaterials all the dimensions are measured within the nanoscale (no dimensions are larger than 100nm). Most commonly, 0D nanomaterials are nanoparticles.
Hence option B is correct.

Nanolayers are the nanomaterials with only one dimension between 1 nm and 100 nm. Nanotubes or nanowires are the nanomaterials with two dimension between 1 nm and 100 nm. Nanoparticles are the nanomaterials with three dimension between 1 nm and 100 nm.

Three-dimensional nanomaterials (3D) are materials that are not confined to the nanoscale in any dimension. This class can contain bulk powders, dispersions of nanoparticles,bundles of nanowires, and nanotubes as well as multi-nanolayers.
Hence option D is correct.

Two principal factors cause the properties of nanomaterials to differ significantly from other materials: increased relative surface area, and quantum effects. These factors can change or enhance properties such as
reactivity, strength and electrical characteristics.
Hence option C is correct.