12/04/23

Reactivity of MetalsReactivity of Metals

12/04/23Reactions of metals with Reactions of metals with oxygenoxygen

When a metal reacts with oxygen it will form a METAL OXIDE. This is what happens when a metal rusts. We can make this reaction happen quicker by burning the metal.

METAL + OXYGEN METAL OXIDE

Copy and complete the following reactions:

1) Magnesium + oxygen

2) Copper + oxygen

3) Calcium + oxygen

4) Iron + oxygen

12/04/23Reactions of metals with Reactions of metals with waterwater

When a metal reacts with water hydrogen is always given off. The other product will be either a metal hydroxide or a metal oxide.

Copy and complete the following reactions:

1) Sodium + water

2) Potassium + water

3) Calcium + water

4) Iron + steam

METAL + WATER METAL OXIDE + HYDROGEN

METAL + WATER METAL HYDROXIDE + HYDROGEN

12/04/23Reactions of metals with Reactions of metals with acidsacids

When a metal reacts with an acid it gives off hydrogen (which can be “popped” using a lit splint). The other product is a salt.

Copy and complete the following reactions:

1) Calcium + hydrochloric acid

2) Zinc + hydrochloric acid

3) Iron + hydrochloric acid

4) Lithium + sulphuric acid

METAL + ACID SALT + HYDROGEN

e.g. magnesium + hydrochloric acid magnesium chloride + hydrogen

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Complete the following reactions:Complete the following reactions:

1) Lithium + water

2) Lithium + hydrochloric acid

3) Silver + oxygen

4) Magnesium + sulphuric acid

5) Potassium + oxygen

6) Aluminium + oxygen

7) Manganese + water

8) Sodium + sulphuric acid

9) Lithium + oxygen

10)Nickel + hydrochloric acid

Lithium hydroxide + hydrogen

Lithium chloride + hydrogen

Silver oxide

Magnesium sulphate + hydrogen

Potassium oxide

Aluminium oxide

Manganese oxide + hydrogen

Sodium sulphate + hydrogen

Lithium oxide

Nickel chloride + hydrogen

12/04/23An example question on An example question on reactivityreactivity

Metal Reaction with dilute

acid

Reaction with water

Reaction with

oxygen

ASome reaction Slow reaction Burns

brightly

B No reaction No reaction Reacts slowly

C No reaction No reaction No reaction

DViolent reaction

Slow reaction Burns brightly

EReasonable reaction

Reacts with steam only

Reacts slowly

12/04/23

The Reactivity SeriesThe Reactivity Series

The Reactivity Series lists metals in order of reactivity:

Potassium

Sodium

Calcium

Magnesium

Aluminium

Carbon

Zinc

Iron

Lead

Copper

Silver

Gold

12/04/23Displacement reactionsDisplacement reactions

Mg

Magnesium

SO4Cu

Copper sulphate

The magnesium DISPLACES the copper from copper sulphate

SO4Mg

Magnesium sulphate

Cu

Copper

A displacement reaction is one where a MORE REACTIVE metal will DISPLACE a LESS REACTIVE metal from a compound.

12/04/23

Displacement reactionsDisplacement reactions

A displacement reaction is one where a MORE REACTIVE metal will DISPLACE a LESS REACTIVE metal from a compound.

For example, if you drop some magnesium into copper sulphate a reaction will happen because magnesium is more reactive than copper, so the reaction is:

Magnesium + copper sulphate copper + magnesium sulphate

However, if you drop some copper into magnesium sulphate NOTHING will happen.

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Some example reactions…Some example reactions…

Reaction Prediction Observations

Zinc + copper sulphate

Zinc + lead nitrate

Copper + lead nitrate

Copper + silver nitrate

Extension work – write down the equations for these reactions

12/04/23

Some example reactions…Some example reactions…

Reaction Prediction Observations

Zinc + copper sulphate

Reaction DID happen

Zinc + lead nitrate Reaction DID happen

Copper + lead nitrate

Reaction DID NOT happen

Copper + silver nitrate

Reaction DID happen

Extension work – write down the equations for these reactions

12/04/23

Extracting MetalsExtracting Metals

Some definitions:

A METAL ORE is a mineral or mixture of minerals from which it is “economically practical” to extract some metal.

Most ores contain METAL OXIDES (e.g. rust = iron oxide).

To “extract” a metal from a metal oxide we need to REDUCE the oxygen. This is called a REDUCTION reaction.

12/04/23How do we do it?How do we do it?Potassium

Sodium

Calcium

Magnesium

Aluminium

Carbon

Zinc

Iron

Tin

Lead

Copper

Silver

Gold

Platinum

Metals ABOVE CARBON, because of their high reactivity, are extracted by ELECTROLYSIS

Metals BELOW CARBON are extracted by heating them with carbon in a BLAST FURNACE

These LOW REACTIVITY metals blatantly won’t need to be extracted because they are SO unreactive you’ll find them on their own, not in a metal oxide

12/04/23

Extracting metalsExtracting metals

1) What is an ore?

2) In what form are metals usually found in the Earth?

3) How do you get a metal out of a metal oxide?

4) What is this type of reaction called?

Type of metal Extraction process

Examples

High reactivity (i.e anything above

carbon)

Middle reactivity (i.e. anything below

carbon)

Low reactivity

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The Blast FurnaceThe Blast Furnace1) HAEMATITE (iron ore), limestone and coke (carbon) are fed in here

2) Hot air is blasted in here

3) The carbon reacts with oxygen from the air to form carbon dioxide.

4) The carbon dioxide reacts with more carbon to form carbon monoxide

6) Molten slag (waste) is tapped off here

5) Carbon monoxide reduces iron oxide to iron. The molten iron is tapped off here

Iron oxide + carbon monoxide iron + carbon dioxide

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ElectrolysisElectrolysis

Molecule of solid copper chloride

Molecule of solid copper chloride after being dissolved

Chloride ion

Copper ion

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ElectrolysisElectrolysisElectrolysis is used to extract a HIGHLY REACTIVE metal.

= chloride ion

= copper ion

When we electrolysed copper chloride the

negative chloride ions moved to the positive

electrode and the positive copper ions

moved to the negative electrode – OPPOSITES

ATTRACT!!!

12/04/23Redox reactionsRedox reactionsThese happen during electrolysis:

These two processes are called REDOX REACTIONS

OILRIG – Oxidation Is Loss of electrons

Reduction Is Gain of electrons

At the positive electrode the negative ions LOSE electrons to

become neutral – this is OXIDATION

At the negative electrode the positive ions GAIN electrons to

become neutral – this is REDUCTION

12/04/23

Purifying Purifying AluminiuAluminiu

mm

Aluminium has to be extracted from its ore (called ________) by electrolysis. This is because aluminium is very ___________. The ore is mixed with cryolite to lower its ________ ________. The ore is then melted so that the ions can ______. The positively charged aluminium ions gather at the ___________ electrode. Oxygen forms at the positive electrode and causes it to wear away, which means that they have to be __________ frequently.

Words – melting point, replaced, negative, bauxite, reactive, move

12/04/23

Rusting ExperimentRusting Experiment

RUST NO RUST – no water

NO RUST – no oxygen

12/04/23RustingRustingRust is formed when iron reacts with water AND

oxygen. It’s an example of an oxidation reaction which can be sped up using salt. There are several ways of dealing with rust:

1) Regular painting or oiling

2) Galvanising – this is when iron objects are coated with zinc

3) Making objects out of a non-rusting metal, such as stainless steel

4) Attaching zinc bars to ships – the water will react with the zinc before it reacts with the iron, because zinc is more reactive