Metals

Question 1

Why do we use copper pipes

Answer 1

Copper doesn’t react with water

Question 2

Why can a more reactive metal displace a less reactive metal from its salt

Answer 2

As it forms positive ions more easily, the higher up on the reactivity series the more reactive

Question 3

What metal is used in sacrificial protection

Answer 3

Zinc

Question 4

Why are carbon and hydrogen apart of the reactivity series

Answer 4

They are used to extract metal from their oxides

Question 5

What is a measure of how reactive the metal is

Answer 5

The tendency of the metal to lose electrons to form a positive ion

Question 6

When does a displacement reaction occur

Answer 6

When a more reactive metal can displace a less reactive metal ion from its salt

Question 7

Physical properties of metals (3)

Answer 7

Good conductors of heat + electricity
Malleable+ductile
High melting and boiling point

Question 8

Physical properties of metalloids

Answer 8

A mix between metals and non-metals

Question 9

Physical properties of non metals(3)

Answer 9

Do not conduct heat or electricity
Low melting and boiling point
Brittle

Question 10

4 reactions with metals

Answer 10

Cold water
Steam
Oxygen
Acid

Question 11

Reaction of metal with acid

Answer 11

Metal + acid -> Metal salt + hydrogen
Forms metal salt and hydrogen gas

Question 12

Reaction of metal and cold water

Answer 12

Metal + water -> metal hydroxide + hydrogen
Forms metal hydroxide and hydrogen gas

Question 13

Reaction of metal and steam

Answer 13

Forms metal oxide and hydrogen gas
Metal + steam -> metal oxide + hydrogen

Question 14

Reaction of metal and oxygen

Answer 14

Some reactive metals (alkali) react easily, unreactive metals don’t at all
Metal + oxygen -> metal oxide

Question 15

Alloy and advantages of alloys

Answer 15

Mixture of a metal with other elements
Tend to be harder, stronger and more resistive to corrosion and high temperatures

Question 16

Uses of aluminium and the properties most suitable for that use (5)

Answer 16

Aeroplane bodies - high strength to weight ratio and low density
Tin cans - non-toxic, resistant to corrosion and acidic food
Saucepans - good conductor of heat
Window frames - resistant to corrosion
Overhead power cables - good conductor of electricity and low density

Question 17

In what form/state will the salt be after a metal reacts with acid

Answer 17

Aqueous

Question 18

What are the uses of copper (3) and why

Answer 18

Electrical wires - good conductor of electricity, malleable and ductile
Water pipes - easy to work with and bend non-toxic and unreactive (does not react with water)
Cooking pans - malleable, unreactive to water and good conductor of heat

Question 19

Alloy

Answer 19

Mixture of a metal with other elements

Question 20

Advantages of alloys

Answer 20

Harder
Stronger
More resistive to corrosion/high temperatures

Question 21

3 commonly used alloys, and their mixture composition

Answer 21

Brass - copper and zinc
Stainless steel - Iron and other elements usually nickel/carbon/chromium
Aluminium alloy - aluminium + silicon +manganese

Question 22

What does it mean if theres a white shine in stainless steel

Answer 22

It is an alloy containing chromium

Question 23

Uses of 3 alloys and why

Answer 23

Brass - jewelery, musical instruments (corrosion resistant and has conductive properties)
Stainless steel - cutlery (hardness and resistance to rust)
Aluminium alloy - aircraft bodies (alloy is stronger but still has a low density)

Question 24

Why are alloys harder than most pure metals

Answer 24

Alloys contain atoms of different sizes which distorts the normally regular arrangement of atoms in metals making it more difficult for the layers to slide over each other. This means what alloys are harder than most pure metals

Question 25

How can we determine the reactivity of a metal

Answer 25

Reacting metals with water and acids. The more vigorous the reaction the higher up on the reactivity series The greater the change in temperature, the higher up on the series

Question 26

List the reactivity series

Answer 26

Potassium Sodium Lithium Calcium Magnesium Aluminium Carbon Zinc Iron Hydrogen Copper Silver Gold

Question 27

Displacement reactions

Answer 27

When a more reactive metal can displace a less reactive metal ion from its salt The higher up on the RS , the easier it is to lose electrons (forms cation)

Question 28

Reactivity of aluminium

Answer 28

Does not react with water, only slowly reacts with dilute acids. Reacts readily with oxygen forming a protective, thin layer of aluminium oxide. This prevents reaction with water and dilute acids allowing aluminium to behave as if it is an unreactive metal

Question 29

Thermal decomposition of metal compounds formulas (4)

Answer 29

Metal hydroxides -> mtetal oxide + water Metal carbonates -> metal oxide +carbon dioxide Metal nitrates -> metal oxide +nitrogen dioxide + oxygen Group 1 metal nitrates -> metal nitrite + oxygen

Question 30

Colour of oxygen gas

Answer 30

Colourless

Question 31

Colour of nitrogn dioxide gas

Answer 31

Reddish-brownish

Question 32

Thermal stability of group 1 carbonates

Answer 32

Carbonates are more thermally stable than group 2, so the compounds must be heated to undergo decomposition (needs more heat to break down)

Question 33

Rust (Statements and formula)

Answer 33

ONLY HAPPENS WITH IRON Chemical reaction between iron, water and oxygen to form the compound hydrated iron (III) oxide Oxygen and water must be present for reaction to occur Iron is oxidised (loses some of its electrons)

Question 34

Methods of rust prevention (2)

Answer 34

Barriers Galvanising

Question 35

Galvanising Eg.

Answer 35

Process where iron is coated witgh a layer of zinc. As zinc is more reactive than iron it loses its electrons more easily/is more easily oxidised. It corrodes first and protects the less reactive metal from corrosion Zinc bars on the side of ships

Question 36

Sacrificial protection

Answer 36

A more reactive metal can be attached to a less reactive metal, the more reactive metal will oxidise and corrode first and protect the less reactive metal from corrosion Eg. Zinc bars on sides of steel ships

Question 37

Barrier - rust prevention Common methods (4)

Answer 37

Cover iron with barriers that prevent it from coming into contact with water and oxygen If coatings are scratched/washed away the iron is exposed again Oil, paint, plastic, grease

Question 38

Describe the reaction of: Potassium Sodium Calcium With water

Answer 38

Potassium: vigourously (exothermic) to form a colourless, basic, KOH solution Sodium: readily (exothermic) to form NaOH and H gas Calcium: less strongly to form CaOH and H

Question 39

Reaction of magnesium with steam

Answer 39

Burns in steam to produce white magnesium oxide and hydrogen gas