Material Science

Question 1

What are the two main categories of matter?

Answer 1

Pure substances and mixtures

Question 2

Define a pure substance.

Answer 2

A pure substance has a fixed composition and specific properties

Question 3

What are the two types of pure substances?

Answer 3

• Elements
• Compounds

Question 4

Define an element.

Answer 4

An element is made up of only one type of atom

Question 5

Provide two examples of elements.

Answer 5

• Oxygen (O₂)
• Gold (Au)

Question 6

Define a compound.

Answer 6

A compound consists of two or more elements chemically bonded in a fixed ratio

Question 7

Give an example of a compound.

Answer 7

Water (H₂O) or Carbon dioxide (CO₂)

Question 8

What is a mixture?

Answer 8

A mixture contains two or more substances combined physically

Question 9

How can mixtures be separated?

Answer 9

By physical methods such as filtration or evaporation

Question 10

What are homogeneous mixtures also known as?

Answer 10

Solutions

Question 11

Define homogeneous mixtures.

Answer 11

Homogeneous mixtures have a uniform composition throughout

Question 12

Give an example of a homogeneous mixture.

Answer 12

Saltwater or air

Question 13

Define heterogeneous mixtures.

Answer 13

Heterogeneous mixtures have a non-uniform composition

Question 14

Give an example of a heterogeneous mixture.

Answer 14

Salad or sand in water

Question 15

What is the key difference between a pure substance and a mixture?

Answer 15

A pure substance has fixed ratios of elements, while a mixture does not

Question 16

Classify saltwater.

Answer 16

Homogeneous mixture

Question 17

Classify oxygen gas.

Answer 17

Element

Question 18

Classify iron oxide (Fe₂O₃).

Answer 18

Compound

Question 19

Classify a chocolate chip cookie.

Answer 19

Heterogeneous mixture

Question 20

How do homogeneous and heterogeneous mixtures differ?

Answer 20

Homogeneous mixtures have uniform distribution, while heterogeneous mixtures have visibly distinct components

Question 22

What is the definition of nanotechnology?

Answer 22

The branch of materials science dealing with the design, properties and application of materials in the nanoscale.

Nanotechnology encompasses various fields including physics, chemistry, and biology.

Question 23

What size range does the nano-scale refer to?

Answer 23

Structures between 1 – 100 nanometres in size.

This size range is critical for unique physical and chemical properties of materials.

Question 24

How is a nanometre defined?

Answer 24

One billionth of a metre (1 x 10^-9 m).

The nanometre is a standard unit for measuring things at the nanoscale.

Question 25

What are nanomaterials?

Answer 25

Materials that consist of single units that exist in the nanoscale. ## Footnote Nanomaterials can have unique properties compared to their bulk counterparts.

Question 26

Give two natural examples of nanomaterials.

Answer 26

* Butterfly wings * Gecko feet ## Footnote These natural examples exhibit unique optical and adhesive properties due to their nanostructure.

Question 27

What is an artificial example of a nanomaterial?

Answer 27

Cylindrical nanotubes. ## Footnote Nanotubes have applications in various fields including electronics and materials science.

Question 28

What are nanoparticles?

Answer 28

Material where the individual particles are of nano-scale. ## Footnote Nanoparticles can exhibit different properties than larger particles of the same material.

Question 29

Why do nanoparticles exhibit different properties compared to larger scale materials?

Answer 29

Due to their much greater surface areas. ## Footnote Increased surface area to volume ratio significantly affects chemical reactivity and physical properties.

Question 30

What potential advantages do nanoparticles have due to their ability to travel?

Answer 30

They can travel through air, skin or even cells. ## Footnote This characteristic makes them useful in drug delivery systems and medical applications.

Question 31

True or False: Nanoparticles are only beneficial and do not pose any risks.

Answer 31

False. ## Footnote While nanoparticles have many potential applications, they can also be potentially dangerous due to their ability to penetrate biological barriers.