Chemistry T8B: Metals & reactivity series

State the reactivity series

Potassium

Sodium

Calcium

Magnesium

Aluminum

[Carbon]

Iron

Tim

Lead

[H+ Ion]

Copper

Mercury

Silver

Gold

Why does Aluminum not seem to react with water or steam?

Aluminum readily reacts with oxygen to form a thin layer of insoluble impervious Aluminum Oxide on the surface of the metal.

The layer prevents further reactions from taking place

Reactive metal + water =

metal hydroxide + hydrogen

What metals in the reactivity series can react with water?

Potassium

Sodium

Calcium

Magnesium

Reactive metal + steam =

Metal oxide + hydrogen

What metals in the reactivity series can react with steam?

Potassium

Sodium

Calcium

Magnesium

Aluminum

Zinc

Iron

Define corrosion

Gradual destruction of a metal due to air, water or other chemicals

Define rusting

Corrosion of iron

What percentage of air is oxygen?

21%

State two factors that speed up rusting and explain why

Ionic/acidic substances & Iron in contact with less reactive metals

Iron will lose electrons to ions/less reactive metals to form more Fe3+ ions, faster, which speeds up rusting

What dictates the reactivity/metallic character of a metal?

How easily a metal atom can lose its valence electrons

What are the displacement reactions of metals?

A more reactive metal displaces the less reactive metals from:

Its salt solution

Metal oxide(thermite reaction)

Define an alloy

A HOMOGENEUOS mixture of metals and other elements

What is brass composed of, and what are its properties?

Copper + Zinc

It is resistant to corrosion

What is bronze composed of, and what are its properties?

Copper + Tin

It is resistant to corrosion

What is steel composed of and what are its properties?

Iron + Carbon + Other impurities

It is hard and strong

Why are pure metals rarely used in real life?

They are relatively soft

They have atoms of the same size arranged in orderly layers

When a force is applied, the layers can slide over one another easily without breaking any metallic bonds

They corrode easily

Why are alloys harder and stronger than pure metals?

They have atoms of different atomic radii that disrupt the orderly layers to atoms

When a force is applied the layers cannot slide over one another easily without breaking any metallic bonds

Name 4 properties of alloys

Harder and stronger

More resistant to corrosion

Lower melting points

Better appearance

Describe the thermite reaction

An exothermic displacement reaction between metals and metal oxides

What makes a metal oxide difficult to reduce via carbon or hydrogen?

The more reactive a metal is, the more difficult its oxide will be to reduce via carbon or hydrogen

Metal oxide + carbon + heat =

Metal + carbon dioxide

Metal oxide + hydrogen + heat =

Metal + steam

What is the experimental setup for reduction of metal oxides by carbon?

Refer to chemistry 21/1 p1

What is the experimental setup for reduction of metal oxides by hydrogen?

Refer to chemistry 21/1 p1

Why must hydrogen be burnt off?

It is highly flammable and explosive in large quantities

Why must hydrogen gas be dried in the reduction of metal oxides by hydrogen?

To prevent water in wet hydrogen gas from turning into steam upon heating and reacting with the metal to form a metal oxide and hydrogen

State the metals(of the reactivity series)whose oxides cannot be reduced via carbon or hydrogen

Carbon:

Potassium

Sodium

Calcium

Magnesium

Aluminium

Hydrogen:

Potassium

Sodium

Calcium

Magnesium

Aluminium

Zinc

What makes a compound thermally stable?

The thermal stability of a compound increases with the reactivity of the metal within it

Metal carbonate + heat =

Metal + carbon dioxide

With Silver, Gold, Platinum carbonate

Metal + carbon dioxide + oxygen

Metal oxide + heat =

Metal + oxygen

State the metals(of the reactivity series)whose oxides or carbonates are thermally stable

Oxides:

Potassium

Sodium

Calcium

Magnesium

Aluminium

Zinc

Iron

Tin

Lead

Copper

Carbonates:

Potassium

Sodium

State and explain the three methods of rust prevention

Surface protection

- Prevents object from being exposed to water and oxygen

Sacrificial protection

- A more more reactive metal corrodes in place of a less reactive metal

Alloying

- Iron, carbon and nickel are mixed to form stainless steel which is rust resistant.

What metals in the reactivity series can react with steam?

Potassium

Sodium

Calcium

Magnesium

Aluminum

Zinc

Iron