C2c - Metals and alloys

Question 1

What is an anode

Answer 1

Positive electrode

Question 2

What is a cathode

Answer 2

Negative electrode

Question 3

How is electrolysis used in the purification of copper(8)

Answer 3

impure copper as anode;pure copper as cathode;copper(II) sulfate solution as electrolyte

cathode gains mass as copper is deposited

• Cu2+ + 2e- –> Cu
• reduction - electrons are gained

anode loses mass as copper dissolves

• Cu - 2e- –> Cu2+
• oxidation - electrons are lost

impurities dropped at anode as a sludge

Question 4

Advantages of recycling copper (4)

Answer 4

saves natural resources

best copper ores have been used up; remaining ores contain less copper and are more difficult to mine

reduces amount of waste and pollution produced during extraction of copper

cheaper as it uses less energy compared with extraction from its ores

Question 5

Disadvantages of recycling copper (3)

Answer 5

small amounts used in electrical equipment hard to separate

less copper mining decreases jobs

separating process to sort out the copper from all the other waste metal takes time, energy and causes pollution

Question 6

What is an alloy

Answer 6

mixture containing one or more metal elements

Question 7

What are the main metals in amalgam and what is amalgam mainly used for

Answer 7

mercury

used in tooth fillings

Question 8

What are the main metals in solder and what is solder mainly used for

Answer 8

lead and tin

used to join electrical wires

Question 9

What are the main metals in brass and what is brassmainly used for

Answer 9

copper and zinc

musical instruments, coins and door decorations

Question 10

Explain how the use of ‘smart alloys’ such as those with a shape memory property have increased the number of applications of alloys(2)

Answer 10

if shape memory allows are bent out of shape, they return to original shape when warmed

nitinol (nickel and titanium) is used to make spectacle frames so that they will return to their original shape after bending