Topic 6 - Materials

Question 1

What is the reactivity series of metals?

Answer 1

Potassium (K)
Sodium (Na)
Calcium (Ca)
Magnesium (Mg)
Aluminium (Al)
*Carbon
Zinc (Zn)
Iron (Fe)
Tin (Sn)
Lead (Pb)
*hydrogen
Copper (Cu)
Silver (Au)
Gold (Au)
Platinum (Pt)

Question 2

What is the test for hydrogen gas?

Answer 2

Lit splint gives a squeaky pop

Question 3

Core practical: Method to test 3 metals to determine order of reactivity?

Answer 3

1) Add 5cm3 of acid to the test tube.
2) Record the temperature of the acid.
3) Add a spatula or the metal filling and record your observations and new temperature.

Question 4

What is a displacement reaction?

Answer 4

When a more reactive metal in the reactivity series will displace a less reactive metal from its compound.

Question 5

Example of a displacement reaction.

Answer 5

Potassium + Copper chloride —> Copper + potassium chloride.

Question 6

What is oxidation?

Answer 6

A reaction where a substance gains oxygen.

Question 7

What is reduction?

Answer 7

A reaction where a substance loses oxygen.

Question 8

Example of oxidation and reduction.

Answer 8

Copper oxide + Carbon -> Copper + Carbon dioxide

Carbon was oxidised
Copper was reduced

Question 9

Is oxidation a loss or gain of electrons?

Answer 9

A loss of electrons.

Question 10

Is reduction a loss or gain of electrons?

Answer 10

A gain of electrons.

Question 11

How to remember if oxidation and reduction are a loss or gain?

Answer 11

O.I.L.R.I.G

Question 12

What is an ore?

Answer 12

An ore is a rock that contains enough of a metal compound to extract a metal for profit.

More reactive metals will reactive with other elements to form compounds in rocks.
Unreactive metals are found in the earths crust as the uncombined elements.

Question 13

What does extraction mean?

Answer 13

Process of obtaining a metal from a compound.

Question 14

Equation for extraction copper from copper oxide with carbon?

Answer 14

Copper oxide + Carbon —> Copper + Carbon dioxide

Question 15

What is meant by recycling metals?

Answer 15

When metals can be recycled by melting them down and making them into something new.

Question 16

What are advantages of recycling?

Answer 16

• Saves energy, which reduces burning of fossil fuels which are running out and contribute to acid rain and climate change.
• As there is a finite amount of raw materials it conserves these resources.
• Extracting metals impacts the environment. Mines are damaging to the environment and destroy habitats. Recycling metals means we won’t need mines.
• Cuts down the amount of rubbish sent to landfill which takes up space and pollutes surroundings.
• Saves money on energy.
• Beneficial to the economy metals that are expensive to extract or buy.
• Recycling creates lots of jobs.

Question 17

What are the disadvantages of recycling?

Answer 17

• Costs and energy used in collecting, transporting and sorting metals to be recycled.
• Can be more expensive and require more energy to recycle than to extract new metal.

Question 18

What is a lifecycle assessment?

Answer 18

A life cycle assessment looks at each stage of the life of a product - from making the material from natural raw materials, to making the product from the materia, using the product and disposing of the product. It works out the potential environmental impact of each stage.

Question 19

What are the stages of the life cycle assessment?

Answer 19

• Obtaining and processing raw materials
• Manufacturing and packaging
• Using the product
• Disposal of the product

Question 20

Limitations of the lifecycle assessment?

Answer 20

• Making products involves loads of different steps and it’s almost impossible to quantify them.
• Difficult to assess the harm of each step.
• Complex which means can be manipulated to deliberately support a company.

Question 21

Why should the life cycle assessment be carried out before making a product?

Answer 21

• Help people decide whether it’s worthwhile to manufacture and recycle product.
• Can be used to compare the effect of using different materials for the same product.

Question 22

What are allotropes?

Answer 22

Allotropes are different structural forms of the same element.

Question 23

What are allotropes of carbon?

Answer 23

Diamond
Graphite
Fullerenes
Graphene

Question 24

Diamond properties?

Answer 24

• Giant covalent structure
• Each carbon atom is joined to four other carbon atoms by strong covalent bonds.
• No free electrons - does not conduct electricity.
• High melting point
• Hard - no intermolecular forces
• Strong covalent bonds so strong material.

Question 25

What is diamond used for and why?

Answer 25

• Cutting tools - The rigid network of carbon atoms, held together by strong covalent bonds, makes diamond very hard. • Jewellery

Question 26

Graphite properties?

Answer 26

• Giant covalent structure • Each carbon atom forms 3 covalent bonds to other carbon atoms • Conducts electricity - delocalised electron • High melting point • Strong covalent bonds • Weak intermolecular forces - No covalent bonds between layers • Soft

Question 27

What are graphites uses and why?

Answer 27

• Electrodes - Each carbon atoms forms 3 covalent bonds to other carbon atoms which means that there is one delocalised electron from each atoms so it can conduct electricity. • Lubricant + pencils - Graphite has weak intermolecular forces so the layers can slide over each other which makes it slippery.

Question 28

Graphene properties?

Answer 28

• Single layer of graphite • Giant covalent structure • Each carbon atom forms 3 covalent bonds to other carbon atoms • Strong covalent bonds • High melting point • Conducts electricity • Strong

Question 29

What are Graphenes uses and why?

Answer 29

• Electronics - Each carbon atoms forms 3 covalent bonds to other carbon atoms which means that there is one delocalised electron from each atoms so it can conduct electricity. • Making composites - (material made from 3 or more different materials with contrasting properties).

Question 30

Buckminster fullerene properties?

Answer 30

• 60 carbon atoms joined together by strong covalent bonds. • Molecules of carbon atoms with hollow shapes. • Hexagonal rings of carbon atoms. • Weak intermolecular forces - strength is very low. • Low melting point • Each carbon atoms is joined to 3 others so has 1 free electron. • Only conducts electricity across the surface of the molecule. Little movement of electrons between molecules. Poor conductor of electricity. • Molecular structure

Question 31

What are the uses of buckminster fullerene?

Answer 31

• Drug delivery into the body • Lubricants • Catalysts They can act as hollow cages to trap other molecules. This is how they can carry drug molecules around the body and delivery them to where they are needed, and trap dangerous substances in the body and remove them.

Question 32

How is a metals relative resistance to oxidation related to its position in the reactivity series?

Answer 32

The less reactive a metal is, the more resistant it is too oxidation, because for a metal to react it forms a positive metal ion by loosing electrons (oxidation).

Question 33

Alternative biological methods of metal extraction?

Answer 33

• Phytoextraction This involves growing plants in soil that contains metal compounds. The plants can’t use or get rid the metals so they gradually build up in the leaves. The plants can be harvested, dried and burned in a furnace. The ash contains metal compounds from which the metal can be extracted by electrolysis or displacement reactions. • Bacterial extraction, bioleaching The bacteria get energy from the bonds between the atoms in the ore, separating out the metal from the ore in the process. The leachate contains metal ions which can be extracted with a more reactive metal.

Question 34

Why is the method used to extract a metal from its ore related to its position in the reactivity series and the cost of extraction process?

Answer 34

• Metals higher than carbon in the reactivity series can be extracted using electrolysis which is expensive • Metals below carbon in the reactivity series can be extracted using carbon.

Question 35

Obtaining and processing raw materials?

Answer 35

• Using up limited resources such as ores and crude oil. • Damaging habitats through deforestation or mining.

Question 36

Manufacturing?

Answer 36

• Using up land for factories • The use of fossil fuelled machines for production and transport • Porduction of waste

Question 37

Product use?

Answer 37

Using the product can also damage the environment. For example: 1) Paint gives off toxic fumes. 2) Burning fuels releases greenhouse gasses and other harmful substances. 3) Fertilisers can leach into streams and cause damage to ecosystems.

Question 38

Disposal?

Answer 38

• Using up space at landfill sites • Wether the product or parts can be recycled

Question 39

Advantages and disadvantages of dott and cross diagrams

Answer 39

+ Useful for illustrating the transfer of electrons + Where the electrons in the bonds come from - Fails to illustrate the 3D arrangements of the atoms and electron shells - Doesn’t include the relative sizes of the atoms

Question 40

Advantages and disadvantages of the ball and stick model

Answer 40

+ Useful for illustrating the arrangement of atoms in 3D space + Especially useful for visualising the shape of a molecule. - Fails at indicating the movement of electrons - The atoms are placed far apart from each other, which in reality is not the case as the gaps between the atoms are much smaller

Question 41

Advantages and disadvantages of 2D representations?

Answer 41

+ Simple and a great way of showing what atoms something contains + How the atoms are connected - Don’t show shape of the substance - Don’t give any idea about the sizes of the atoms

Question 42

Advantages and disadvantages of 3D models?

Answer 42

+ Show the arrangement of ions - Only show the outer layer of the substance

Question 43

Uncombined elements

Answer 43

Silver Gold Platinum

Question 44

Metals to extract with carbon

Answer 44

Zinc Iron Tin Lead Copper

Question 45

Metals to extract by electrolysis

Answer 45

Potassium Sodium Calcium Magnesium Aluminium

Question 46

Form of reduction

Answer 46

Extraction

Question 47

Form of oxidation

Answer 47

Corrosion e.g. rust