Unit 4

Question 1

what is an alloy ?

Answer 1

an alloy is a mixture of two or more elements, at least one of which is a metal

Question 2

What do alloys have in compared to pure metals ?

Answer 2

alloys have different physical properties in comparison to pure metals

Question 3

Explain how the properties of metals are linked to their uses

Answer 3

Different metals have different properties which makes one particular metal metal more suited to a certain function than others.

E.G. Copper are good electrical conductors and resist corrosion, so they are used in wires

Question 4

Use observations from reactions of metals with water, oxygen and acid to place the metals in order of reactivity

Answer 4

-Potassium
-Sodium
-Lithium
-Calcium
-Magnesium
-Carbon
-Zinc
-Iron
-Hydrogen
-Copper
-Gold

Question 5

h

Answer 5

h

Question 6

Describe the process of extracting a metal using heat and state examples of metals which this method would be used for

Answer 6

Some metals low down in the reactivity series can be extracted by heating alone. E.g silver

Question 7

State how the method of extraction relates to the position of the metal in the reactivity series

Answer 7

-Metals high up on the reactivity series, such as aluminium must be extracted using electrolysis
-metals in the middle can be extracted using heat with carbon
-Metals at the bottom can be extracted using heat alone

Question 8

Describe what is meant by corrosion of a metal

Answer 8

corrosion is a slow chemical reaction which involves the surface of a metal changing from an element to a compound

Question 9

State the conditions which must be present for corrosion to occur

Answer 9

Water and oxygen are required for rusting to occur.

Question 10

Describe ways in which metals can be protected from corrosion

Answer 10

Barrier methods prevent water and oxygen getting to the surface of an ion
e.g.
-painting
-oiling
-plastic coating
-galvanised zinc coating
-tin plating (coating in tin)

Question 11

What is a battery ?

Answer 11

a battery (cell) is a portable energy source which has a store of chemical energy

Question 12

State what is meant by a novel/smart material

Answer 12

Smart materials are materials that have properties that can change significantly

(at some point do novel materials)

Question 13

State some examples of novel/smart materials

Answer 13

hydrogel

Question 14

Describe some useful properties of novel/smart materials

Answer 14

-Thermal and electrical conductivity
-thermal expansion

Question 15

Describe which properties of ceramic materials have made them vital in many modern applications

Answer 15

-Resistant to heat, and corrosion
-they are hard

Question 16

Describe some applications of chemical analysis

Answer 16

-making and working with fertiliser
-monitoring the environment
-the making of felt tip pens

Question 17

Describe the importance of chemical analysis with reference to testing for pollutants

Answer 17

chemical analysis allows chemists to discover pollution and tit can also help with making sure ecosystems are viable for organisms to live there.

Question 18

Describe the process of extracting a metal using heating with carbon and state examples of metals which this method would be used for

Answer 18

Metals that are less reactive than carbon can be extracted from their ores by heating with carbon. The carbon is referred to as a reducing agent.

Question 19

Describe the process of extracting a metal using electrolysis and state examples of metals which this method would be used for

Answer 19

Metals that are more reactive than carbon are
extracted using electrolysis.

This uses electricity to break up the ore.
e.g. aluminium, magnesium