Nanomaterials

Question 1

What are nanomaterials?

Answer 1

Nanomaterials are defined as substances that have at least 1 dimension ranging from 1-100nm.

Question 2

What are nanoparticles?

Answer 2

Nanoparticles are defined as particles having all dimensions within 1-100nm.

Question 3

What is the most important property of nanomaterials and nanoparticles?

Answer 3

Extremely small size –> surface area to volume ratio is very large –> highly reactive

Question 4

Catalytic converter & adsorption?

Answer 4

• Adsorption of gaseous reactant molecules onto catalyst surface with solid Pt nanoparticles increases reaction rate:
  1. Adsorption weakens covalent bonds within reactant, reducing activation energy
  2. Adsorption increases concentration of reactant, allows for reactants to come into close contact with proper orientation

Example of heterogeneous catalysis

Question 5

How do geckos withstand their weight when climbing?

Answer 5

Septulae produce large surface area –> weak id id interactions between molecules on septulae n molecules of surface become strong as there are many septulae –> support weight of gecko

Question 6

Define allotropes.

Answer 6

It is defined as different forms of the same element that have different structures.

Question 7

Describe the structure of graphene.

Answer 7

It is a 2D compound, one atom thick and is considered to be a single layer of graphite.

Question 8

State the properties of graphene.

applies to carbon nanotubes

Answer 8

1. High electrical conductivity
2. High tensile strength
3. Lightweight and thin
4. High transparency

Question 9

Explain why high electrical conductivity is a property of graphene.

applies to carbon nanotubes

Answer 9

Valence electron of each C atom located in a p-orbital that overlaps with p-orbitals of adjacent C atoms to form a continuous valence electron cloud –> e- are delocalised along graphene layer, act as mobile charge carriers

Question 10

Explain why high tensile strength is a property of graphene.

applies to carbon nanotubes and buckministerfullerene

Answer 10

GMS –> network of strong covalent bonds where each C atom is covalently bonded to 3 other C atoms –> requires large amount of energy to break covalent bonds –> can flex easily without covalent bonds breaking apart

Question 11

Define tensile strength.

Answer 11

Tensile strength is defined as the maximum stress that a material can withstand while being stretched or pulled before breaking.

Question 12

Explain why lightweight and thin is a property of graphene.

Answer 12

This is because graphene consists of a single layer of carbon atoms in a hexagonal network and carbon has a low atomic mass of 12.

Question 13

Explain why high transparency is a property of graphene.

Answer 13

Graphene consists of a single layer of carbon atoms and 98% of visible light can pass through graphene.

Question 14

Describe the structure of buckministerfullerene.

Answer 14

Simple molecular structure with id id interactions between molecules

Question 15

State the properties of buckministerfullerene.

Answer 15

• No electrical conductivity
• High tensile strength

Question 16

Explain why buckministerfullerene has no electrical conductivity.

Answer 16

Valence electron on each C atom located in a p-orbital that overlaps with adjacent C atoms to form continuous valence electron cloud within each molecule –> e- are unable to delocalise between molecules –> unable to conduct electricity

Question 17

How can nanomaterials enter the human body?

Answer 17

• Pores on the skin
• Inhalation
• Ingestion

Question 18

How do nanomaterials cause harm to the human body?

Answer 18

Small size of nanoparticles can travel from the entry portals via the bloodstream and end up in body tissues and cause damage to cells and organs.

Question 19

What are the risks of nanomaterials on the environment?

Answer 19

Current waste and sewage treatment plants are not able to trap and prevent the small nanoparticles from being released into the environment.