Design materials and chemical equations

Question 1

Design materials

Answer 1

design materials are materials created by humans to have certain properties in order to perform a function.

Question 2

The properties of a substance are determined by ____

Answer 2

its molecular structure

Question 3

Examples of certain properties

Answer 3

• Strength
• Flexibility
• Hardness
• Transparency

Question 4

Aspects of molecular structure

Answer 4

1. Composition
2. Bonding
3. Crystal structure

Question 5

Composition

Answer 5

The composition of a substance is the particular types of atoms and molecules in a substance.

Question 6

Bonding

Answer 6

The bonding in a substance is the type and strength of intramolecular and intermolecular forces between the particles.

Question 7

Crystal structure

Answer 7

The crystal structure is the arrangement or order of the atoms and molecules in the substance.

Question 8

Crystalline structure

Answer 8

well ordered with repeating symmetrical patterns. Substances with a crystalline structure are stronger and stiffer.

Question 9

Non-crystalline structure (amorphous)

Answer 9

when atoms and molecules are randomly arranged. Amorphous structures are weaker but more flexible.

Question 10

Metal bonding type(s)

Answer 10

Metallic

Question 11

Ceramic bonding type(s)

Answer 11

Ionic and covalent

Question 12

Polymer bonding type(s)

Answer 12

Covalent and intermolecular

Question 13

Metals are strong ____

Answer 13

because the negative “electron sea” completely surrounds the positive ions.

Question 14

Metals are conductive_____

Answer 14

because the “electron sea” can flow from atom to atom.

Question 15

Metals are not transparent____

Answer 15

because metals hold onto their electrons loosely and the loose electrons can vibrate at many frequencies so metals have more available energy states and can absorb more EM radiation.

Question 16

Metals are reshapeable______

Answer 16

because the metal ions can move around in the “electron sea” without breaking bonds

Question 17

Metals tend to_____

Answer 17

bend instead of crack/shatter

Question 18

Metal crystals and alloys (2)

Answer 18

1. Metals that have a crystal structure are stronger, but less able to flex
2. Borders between metal crystals are called grains, which are weak spots and can be strengthed by adding an atom of a different metal. This type of metal is called an alloy

Question 19

Ceramics (2)

Answer 19

1. Ceramics are made of both metal and non-metal atoms, bonded by ionic and covalent bonds.
2. Ceramics and glasses have the similar composition, but ceramics have a crystalline structure while glass has an amorphous structure.

Question 20

Ceramics are hard___

Answer 20

because the positive and negative ions alternate with very strong forces meaning they are where they want to be so they don’t want to move.

Question 21

Ceramics are not reshapable_____

Answer 21

because atoms cannot move without breaking bonds so ceramics tend to crack instead of bending/deforming.

Question 22

Ceramics are transparent ____

Answer 22

because the electrons in ceramics and glasses are held tightly so they absorb few frequencies of EM radiation.

Question 23

Ceramics are not conductive___

Answer 23

because they hold onto electrons tightly, not allowing electricity/heat to flow through.

Question 24

Polymers (4)

Answer 24

1. Polymers are long chains of atoms that are covalently bonded together.
2. Polymers typically have a “backbone” made from carbon
3. Polymers connect to each other by intermolecular forces
4. Cross-linking makes the substance stiffer and stronger but less flexible

Question 25

Polymers are strong to tension forces____

Answer 25

because of the long chain molecules but are weak to other forces, unless cross-linked.

Question 26

Polymers are not conductive _____

Answer 26

because the electrons are not free to move.

Question 27

Polymers are transparent____

Answer 27

because the electrons in polymers are held more tightly, so they absorb few frequencies of EM radiation

Question 28

Polymers are flexible____

Answer 28

because the polymer molecules are long and thin, so they can be easily bent unless cross-linked.

Question 29

Law of conservation of mass

Answer 29

Mass cannot be created or destroyed but it can change forms.

Question 30

Chemical reactions

Answer 30

In a chemical reaction new substances are created by breaking old chemical bonds and making new chemical bonds.

Question 31

Reactants

Answer 31

Substances that exist before the reaction.

Question 32

Products

Answer 32

Substances that exist after the reaction.