Tag: materials

Questions Related to materials

At high altitudes, water boils at a lower temperature because

chemistry materials liquid crystals liquid state the liquid state

  1. the atmospheric pressure is high at high altitudes

  2. the viscosity of water is reduced at high altitudes

  3. the atmospheric pressure is low at high altitudes

  4. the surface tension of water is reduced at high altitudes

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Correct Option: C
Explanation:

The boiling of water depends on the atmospheric pressure at that altitude. At high altitudes, the pressure is lower, so water can not boil at $100°$. As the altitude increases, the boiling point of water reduces.

Liquids are similar to gases because:

chemistry materials liquid crystals liquid state the liquid state

  1. both possess the property of flowing and take the volume of the containers

  2. both diffuse and take the shape of the containers

  3. both are readily compressible and diffuse

  4. both are capable of infinite expansion

Show answer
Correct Option: B
Explanation:

Liquids and gases are similar in both shape and volume because they both have its' shape determined by its' surroundings. 

$\Longrightarrow $ Both diffuses and take the shape of containers.

Atmospheric pressures recorded in different cities are as follows:

Cities Shimla Bangalore Delhi Mumbai
$p$ in $N/m^{2}$ $1.01\times 10^{5}$ $1.2\times 10^{5}$ $1.02\times 10^{5}$ $1.21\times 10^{5}$


Consider the above data and mark the place at which liquid will boil first.

chemistry materials liquid crystals liquid state the liquid state

  1. Shimla

  2. Bangalore

  3. Delhi

  4. Mumbai

Show answer
Correct Option: A
Explanation:

The boiling point of a liquid is the temperature at which vapour pressure becomes equal to the atmospheric pressure. Lower the atmospheric pressure, lower is the boiling point.

Since the atmospheric pressure of the Shimla is minimum, thus the boiling point of the liquid will be lowest at Shimla.

Metallic liquids contain:

chemistry materials liquid crystals liquid state the liquid state

  1. metal atoms

  2. ions and mobile electrons

  3. aggregates of metal atom

  4. none of these

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Correct Option: B
Explanation:

When metals are in liquids, they dissociate into ions and give away electrons. So, metallic liquids contain ions and mobile electrons.

Ex: $Na _{(s)}\longrightarrow Na^+ _{(ag)}+e^-$
Ex: $Mg _{(s)}\longrightarrow Mg^{+2} _{(ag)}+2e^-$

When a solid crystal is melted, it should become a liquid. Liquid crystals are an intermediate stage between a liquid and a crystal. Which of the following is a liquid crystal of a non-living system?

chemistry materials liquid crystals liquid state the liquid state

  1. Cholesteryl bromide

  2. Axons of nerve

  3. Striated muscle fibre

  4. Cilia

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Correct Option: A
Explanation:

Axons of nerve, striated muscle fibre, cilia all belong to bio-logical living systems.

Cholesteryl bromide $(C _{27}H _{45}Br)$ is a liquid crystal of a non-living system.

Quantum dot is a___________.

nanochemistry nanotechnology applied chemistry materials chemistry

  1. Nano particle

  2. Semi conductor

  3. A,B

  4. Insulator

Show answer
Correct Option: C
Explanation:

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.

Nano wires and Nano tubes are:

nanochemistry nanotechnology applied chemistry materials chemistry

  1. materials that are nanoscale in two dimensions

  2. materials that have one dimension in the nanoscale

  3. materials that are nanoscale in three dimensions

  4. all the above

Show answer
Correct Option: A
Explanation:

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

$\text{1.Measurment in nano scale.}$ 
$\text{2.Two dimensional.}$

The advantages of using nanoparticles as a drug delivery system include:

nanochemistry nanotechnology applied chemistry materials chemistry

  1. the size and surface characteristics of nanoparticles can be easily manipulated. This could be used for both passive and active drug targeting

  2. 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.

  3. choosing an appropriate matrix also helps in increasing the efficacy and reducing side effects

  4. all of the above

Show answer
Correct Option: D
Explanation:
  • 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.

Increased relative surface area, and quantum effects of nano particles increase the which of the following properties :

nanochemistry nanotechnology applied chemistry materials chemistry

  1. reactivity of the Nano particles

  2. strength of the Nano particles

  3. electrical characteristics of the Nano particles

  4. All the above

Show answer
Correct Option: D
Explanation:

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 :

reactivity of the Nano particles, strength of the Nano particles, electrical characteristics of the Nano particles.
Hence option D  is correct.

Materials which  have one dimension in the nanoscale (and are extended in the other two dimensions) are:

nanochemistry nanotechnology applied chemistry materials chemistry

  1. Graphene

  2. Thin films

  3. Surface coatings

  4. All of the above

Show answer
Correct Option: D
Explanation:

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