C6 - Metals & The Reactivity Series

Front 1

Describe metallic bonding

Back 1

Metals form a third type of giant structure. The metal atoms are packed closely together in a regular arrangement. Because they are so close together, the valence electrons tend to move away from their atoms. A 'sea' of free, delocalised electrons is formed surrounding a lattice of positively charged metal ions. The positively charged ions are held together by their strong attraction to the mobile electrons which move in between the ions. The electrostatic attraction between the electrons and the metal ions act in all directions.

Front 2

Use the structure in metallic bonds to describe the electrical conductivity and malleability of metals

Back 2

* Metals are good conductors of electricity - when a voltage is applied, the delocalised electrons move through the metal lattice towards the positive pole of the cell or power pack.
* Metals are malleable - the positive ions in a metal are arranged regularly in layers. When a force is applied, the layers can slide over each other. In a metallic bond, the attractive forces between the metal ions and the electrons act in any direction, so when the layers slide new bonds can be easily made.

Front 3

List the general physical properties of metals

Back 3

Metals are:

* good conductors of electricity and heat
* malleable - can be hammered into shape
* ductile - can be drawn into different shapes
* lustrous - has a shiny surface when polished
* sonorous - makes a ringing sound when hit

Front 4

Describe the general chemical properties of metals

Back 4

* Many metal oxides are basic
* Many non-metals are acidic
* Many metals react with acids to give off hydrogen gas
* When they react, metals form positive ions by losing electrons

Front 5

Explain in terms of their properties why alloys are used instead of pure metals

Back 5

A mixture of two or more metals, or one or more metals with a nonmetal, is called an alloy. The properties of a metal are changed by making it into an alloy. Metals are made into alloys to combine advantages of different metals and to get rid of their shortcomings.

Front 6

Identify representations of alloys from diagrams of structure

Back 6

An alloy is not just a mixture of metal crystals. The atoms of the second metal form part of the crystal lattice.

Front 7

Describe the transition elements

Back 7

The transition elements are acollection of metals that have high densities, high melting points, form coloured compounds, and which, as elements and compounds, often act ascatalysts.

Front 8

Place in order of reactivity: potassium, sodium, calcium, magnesium, zinc, iron, (hydrogen) and copper, by reference to the reactions, if any, of the metals with:

* water

Back 8

All metals under Hydrogen do not react with water, and all above do. When reacted with water, a metal hydroxide and hydrogen are produced.

Front 9

Place in order of reactivity: potassium, sodium, calcium, magnesium, zinc, iron, (hydrogen) and copper, by reference to the reactions, if any, of the metals with:

* steam

Back 9

All metals above zinc, itself included, react with steam to produce a metal oxide and hydrogen. At the top of the reactivity series the metals react very violently with steam, and as the list goes down towards zinc, the reaction with steam becomes less and less vigorous. Zinc itself needs to be powdered and heated strongly to react in steam for a reaction to occur.

Front 10

Place in order of reactivity: potassium, sodium, calcium, magnesium, zinc, iron, (hydrogen) and copper, by reference to the reactions, if any, of the metals with:

* dilute hydrochloric acid

Back 10

All metals above iron, itself included, react with dilute hydrochloric acid to produce a metal chloride and hydrogen. At the top of the reactivity series the metals react very violently with hydrochloric acid, and as the list goes down towards iron, the reaction with hydrochloric acid becomes less and less vigorous.

Front 11

Describe and explain the use of carbon as a reducing agent for some metal oxides

Back 11

We can carry out reduction using carbon as a reductant (reducing agent). For example, carbon is more reactive than copper, so carbon removes the oxygen from copper (II) oxide when heated.

2CuO + C --> 2Cu + CO₂

Only the oxides of the metals below carbon can be reduced to the metal by heating with carbon. Metals more reactive than carbon have to be extracted by electrolysis.

Front 12

Deduce an order of reactivity from a given set of experimental results

Back 12

The more vigorous a reaction of a metal and another substance, the more reactive that metal is. If we have a few metals and the results of their reactions, we can compare them and deduce their order of reactivity.

Front 13

Describe the reactivity series as related to the tendency of a metal to form its positive ion, illustrated by its reaction, if any, with:

• the oxides of other metals listed

Back 13

In the 'thermit' reaction the aluminium displaces the iron from the iron(III) oxide

Fe₂O₃ + 2Al --> 2Fe Al₂O₃

Front 14

Describe the reactivity series as related to the tendency of a metal to form its positive ion, illustrated by its reaction, if any, with:

* the aqueous ions

Back 14

Zinc is higher in the reactivity series than copper, so it displaces copper from the copper(II) sulfate solution. The solution turns colourless because colourless zinc sulfate is formed.

Zn + CuSO₄ --> ZnSO₄ + Cu

Front 15

Describe and explain the action of heat on the hydroxides, carbonates and nitrates of the listed metals

Back 15

When we heat some hydroxides, carbonates and nitrates they break down to form two or more different products. We call this type of reaction thermal decomposition.

* Hydroxides decompose to form a metal oxide and water
* Carbonates decompose to form a metal oxide and carbon dioxide
* Alkali metal nitrates decompose to form a metal nitrite and oxygen, and other metal decompose to form a metal oxide, nitrogen dioxide and oxygen.

Front 16

Account for the apparent unreactivity of aluminium

Back 16

Aluminium is high in the reactivity series but it does not seem to react with water or acids. It will react with acids only when it is freshly made. This is because, when the surface of freshly made aluminium is left in the air, a thin layer of unreactive aluminium oxide quickly forms on its surface.

Front 17

Describe the ease in obtaining metals from their ores by relating the elements to thereactivity series

Back 17

The way we extract a metal from its ore depends on the position of the metal in the reactivity series. Carbon is used to reduce oxides of metals below it in the reactivity series. Metals above carbon are extracted through electrolysis.

Front 18

Describe and state the essential reactions in the extraction of iron from hematite

Back 18

Hematite is largely iron(III) oxide. We extract iron by reduction of the iron(III) oxide with carbon.

The chemical reactions below result in the production of iron from iron(III) oxide:

* At the bottom of the furnace, coke burns in the hot air blast to form carbon dioxide. The heat released helps heat the furnace. (C + O₂ --> CO₂)
* The carbon dioxide reacts with the coke to form carbon monoxide (CO₂ + C --> 2CO)
* The carbon monoxide reduces the iron (III) oxide to iron. (Fe₂O₃ + 3CO --> Fe + 3CO₂)

Front 19

Describe the conversion of iron into steel using basic oxides and oxygen

Back 19

We make steel using a basic oxygen converter, often called a steelmaking furnace.

* The converter is tipped to one side and molten iron and scrap iron are poured in
* The converter is put back into a vertical position. A water-cooled tube is lowered into the converter
* Oxygen and powdered calcium oxide are blown onto the surface of the molten iron through the tube
* The oxygen oxidises carbon, sulfur, silicon and phosphorus to their oxides (carbon dioxide and sulfur dioxide are gases and escape)
* Silicon and phosphorus oxides are solids. They are acidic oxides. They react with the powdered, basic calcium oxide and a slag is formed (CaSiO₃). The slag floats on the surface of the molten iron and is removed
* The amount of carbon in the steel is controlled by the amount of oxygen blown into the impure iron.

Front 20

Name the uses of calcium carbonate in the manufacture of iron and cement

Back 20

Calcium carbonate, also known as limestone, is used in the manufacture of iron and cement to remove impurities.

Front 21

Know that aluminium is extracted from the ore bauxite by electrolysis

Back 21

The ore of aluminium is called bauxite. Since aluminium is higher than carbon on the reactivity series, it is extracted using electrolysis.

Front 22

Discuss the advantages and disadvantages of recycling metals, limited to iron/steel andaluminium

Back 22

Recycling is the processing of used materials to make new products.

Front 23

Describe in outline, the extraction of zinc from zinc blende

Back 23

* The ore zinc blende (zinc sulfide) is crushed and treated to remove waste rock and impurities
* The zinc oxide is then heated with coke (carbon) in a blast furnace
* A blast of air is blown into the bottom of the furnace. The excess carbon reacts with oxygen in the air to form carbon monoxide (2C + O₂ --> 2CO)
* Higher up, carbon monoxide reduces zinc oxide to zinc and forms carbon dioxide (ZnO + CO --> Zn + CO₂)
* Carbon dioxide formed can react with more carbon to reform carbon dioxide ZnO + C --> Zn + CO)

Front 24

Name the uses of aluminium

Back 24

Aluminium is used for:

* making aircraft bodies because it is lightweight, has a low density, and is quite strong
* making food containers and cooking foil as it has the unreactive layer of aluminium oxide around it and will not react with the acids that are present in many foods

Front 25

Name the uses of copper related to its properties

Back 25

Copper is used for electrical wiring because of its high electrical conductivity. It is one of the most malleable and ductile metals. It is also used for the base of cooking pans because it is a very good conductor of heat.

Front 26

Name the uses of mild steel and stainless steel

Back 26

Mild steel - we use it to make car bodies and part of machinery where it will not be worn away as it is soft and malleable

Stainless steel - we use it in the construction of pipes and towers in chemical factories as it is very strong and can resist corrosion. It is also used to make cutlery.

Front 27

Explain the uses of zinc for galvanising and for making brass

Back 27

Zinc is used to galvanise iron or mild steel to prevent rusting. Galvanised steel is used for roofing because it is weather resistant.

Zinc is also used in the production of brass. Brass is an alloy of copper and zinc. It is stronger than copper and does not corrode.

Front 28

Describe the idea of changing the properties of iron by the controlled use of additivesto form steel alloys

Back 28

After the required amount of carbon has been removed, other metals such as chromium or manganese are added in controlled amounts to the molten iron to make particular alloys of steel with specific properties.