2.4 - Reactivity Series

Question 1

What is the reactivity series?

Answer 1

Potassium
Sodium
Lithium
Calcium
Magnesium
Aluminium
(carbon)
zinc
Iron
(hydrogen)
Copper
Silver
Gold

Question 2

How does Magnesium react in a displacement reaction with metal oxides?

Answer 2

Magnesium powder and Copper(II) oxide are mixed together and heated very strongly at the end traces of magnesium oxide are left on the ceramic paper

Magnesium + Copper(II) oxide > Magnesium oxide + copper

Example of a displacement reaction. Less reactive metal, copper has been displaced from its compound by th more reactive magnesium. Any metal higher in the reactivity series will displace one lower from a compound

However heating copper with magnesium oxide nothing would happen because copper is less reactive than Magnesium. Copper isn’t capable of displacemnt

Question 3

How does Carbon and Copper(II) Oxide react in a displacement reaction?

Answer 3

A black mixture of carbon and copper(II) oxide is heated in a test tube .The mixture glows red hot because of the heat given out during the reaction and left with pink-brown copper in the tube.

C + 2CuO > CO2 + 2Cu
Carbon is above Copper in the reactivity series and displaces copper from Copper(II) Oxide

Question 4

What is Oxidation?

Answer 4

A substance has been oxidised if it gains oxygen. Oxidation is gain of oxygen.

Question 5

What is Reduction?

Answer 5

A substance has been reduced if it loses oxygen. Reduction is loss of oxygen

Question 6

What is OILRIG electrons?

Answer 6

Oxidation
IS
Loss
Reduction
Is
Gain

Question 7

What is a redox reaction?

Answer 7

A redox reaction is one in which both reduction and oxidation occours Oxidation and reduction always occour together because if something loses oxygen, something else must gain

Question 8

What is a reducing agent?

Answer 8

A reducing agent is a substance that reduces something else.
A reducing agent always gets oxidised in a chemical reaction because it takes the oxygen away from something else and therefore gains oxygen itself.

Question 9

What is a oxidising agent?

Answer 9

A substance that oxidises something else.
An oxidising agent always gets reduced in a chemical reaction because it oxidises something else by giving away its oxygen

Question 10

What is oxidation and reduction in terms of electron transfer?

Answer 10

In a reaction between Magnesium and copper (II) oxide. Magnesium and the copper are metals are made of metal atoms. Copper (II) oxide and Magnesium Oxide are both ionic compounds

CuO contains CU2+ and O2- ions, and MGO contains Mg2+ and O2-. O2- ions does not change

Mg atoms are turned into Magnesium ions. Mg atoms lose electrons to form Mg ions. These electrons are gained by the copper ions to form copper atoms redox reaction.

Question 11

How do a displacement reaction occour between Zinc and Copper(II) Sulfate (salt) ?

Answer 11

The Copper is displaced by the more reactive zinc. Blue colour of the Copper (II) sulfate solution fades as colourless zinc sulfate is formed

Zn + CuSO4 > ZnSO4 + Cu
Ionic compounds formed
sulfate is a spectator iron.

Question 12

What is Oxidation and Reduction in terms of electrons?

Answer 12

An oxidising agent is something that oxidises something else by taking its electrons away from it. Oxidising agents accept electrons and therefore are reduced in a reaction

A reducing agent is something that reduces something else by giving electrons to it. Reducing agents give away electrons and therefore are oxidised.

In reaction between Zinc and copper
Zinc reduces copper giving it electrons ZN is reducing agent. Zinc is oxidised.

Question 13

What happenes in a reaction between Copper and Silver Nitrate?

Answer 13

Silver below copper in reactivity series.

CU + 2AgNO3 > Cu(NO3)2 + 2Ag
Nitrate ions are spectator ions

Cu + 2Ag+ > Cu2+ + 2Ag
This is a redox reaction

Cu is reducing agent (it is oxidised) because it gives electrons to the Ag+ ions to reduce them to Ag. Ag+ ion is the oxidising agent (It is reduced) becuase it take away electrons away from the Cu atoms.

Question 14

How do the metals react with water?

Answer 14

Metals above hydrogen in the reactivity series react with water to produce hydrogen. If the metals reacts with cold water metal hydroxide and hydrogen are formed this is the same with steam

Metal + Steam/Cold water . Metal oxide + hydrogen
As moving down the reactivity series reactions become less vigorous

Metals below hydrogen in the reactivity series such as copper don’t react with water or steam

Question 15

How does Potassium, Sodium or Lithium react with cold water?

Answer 15

Very vigorous reactions less violent moving down.

2M + 2H20 > 2MOH + H2

Question 16

How does calcium react with cold water?

Answer 16

Calcium reacts gently with cold water. Grey granules sink but are carrier back to the surface as bubbles of hydrogen are formed around them. Mixture becomes warm.

Calcium hydroxide forms not very soluble in water some does to form a white insoluble solid.

Question 17

How does Magnesium react with cold water?

Answer 17

Almost no reaction. Unless very clean bubbles will form. But reaction stops again this is because magnesium becomes coated with insoluble magnesium hydroxide.

Question 18

How does Magnesium react with steam?

Answer 18

Magnesium ribbon can be heated in steam using delivery tube mineral wool soaked in water.

Mineral wool is not heated directly. Enough heat move back along the test tube to turn the water to steam
Burns with bright white flame producing hydrogen can be ignited to to produce white magnesium oxide.

Question 19

How does Zinc and Iron react with steam?

Answer 19

Zinc and Iron the hydrogen comes off slowly to be collected.

With Zinc
Zinc oxide is formed. This is yellow when its hot white on cooling.

With Iron
Iron becomes slightly darker grey complicated oxide formed

Question 20

Explain the practical: Investigation into reactions between metals and dilute acids

Answer 20

Method:
Set up four test tubes and about 2cm3 of dilute hydrochloric acid into each one
Put a small peice of Magnesium, Zinc, iron or copper into each of the test tube
If fizzing collect or trap gas and test with lighted splint a squeaky pop test indicated H2 gas
Repeat experiments with dilute sulfuric acid

Question 21

What are the reactions for this experiment?

Answer 21

Magnesium - Reacts vigorously with a lot of fizzing. Produces hydrogen. Colourless solution formed very hot test tube

Zinc - Steady reaction. Fizzing. Enough gas eventually collected to produce a squeaky pop with a lighted splint. A colourless solution formed. The test-tube gets warms

Iron - Slow fizzing. Very little gas collected in time available. A very pale green solution formed. Test tube gets slightly warmer.

Copper - No change

These reactions exothermic. Now noticed a temp change measure the temp change to compare the reactivity of the metals.

Question 22

What variables should be controlled in this reaction?

Answer 22

Volume and concentration of hydrochloric acid. The mass of the metal. Surface area of the metal..

Question 23

What procedure can be used to investigate this reaction quantitatively?

Answer 23

Measure out 50cm3 of 1 mol/dm3 hydrochloric acid using a measuring cylinder.
Pour the hydrochloric acid into a polystyrene cup
Measure Inital temperature of hydrochloric acid
Weigh out 0.010 mol of magnesium powder
Add the magnesium powder to the polystyrene cup, stirring rapidly, and measure the maximum tempreture reached
Repeat with other metals using 0.01 metals.

Question 24

How do metals above hydrogen in the reactivity series react with acid?

Answer 24

Metals above hydrogen react with acids to form a salt and hydrogen. Higher the metal in the series the more violent reaction

Metal + Acid > Salt + Hydrogen
Metal + dilute sulfuric acid > metal sulfate + hydrogen

Question 25

How do metals below hydrogen in the reactivity series react with acid?

Answer 25

Metals such as copper and silver and gold do not react with simple dilute acids like hydrochloric and sulfuric

Question 26

How does pottasium, sodium, lithium react with acids?

Answer 26

These are too react to add safely to acids the reaction is too violent. Calcium can be used if the acid is very dilute.

Question 27

How do metals from Magnesium to Iron react with acids?

Answer 27

Magnesium reacts vigorously with cold dilute acids, mixture becomes hot. Colourless solution of magnesium sulfate or chloride forms.

Aluminium is slow to start reacting, but after warming it reacts very vigorously there is a very thin, but very strong, layer of aluminium oxide on the surface of the aluminium, which stops acid getting into it. On heating the acid removes this layer and the aluminium can show its true reactivity.

Zinc and iron react slowly in the cold, but more rapidly on heating. Vigour of reaction less than that of aluminium.

Question 28

How is it possible to find the approximate position of a metal in the reactivity series using water and dilute acids?

Answer 28

Add a very small peice of metal to some cold water. If there is any rapid reaction then the metal must be above magnesium in the reactivity series.

If there is not any reaction, add a small amount of a metal to some dilute hydrochloric acid. If there is not any reaction in cold acid warm it.

If there is still no reaction metal is below hydrogen if there is then it is between hydrogen and magnesium

Question 29

How does Manganese react with copper(II) sulfate solution?

Answer 29

Manganese is above copper in the reactivity series and will displace it from copper(II) sulfate.

Pink brown deposit of copper will be formed. The colour of the solution will fade from blue and leave a very pale pink solution of manganese sulfate.

Mn + CuSO4 > MnSO4 + Cu

Question 30

How does Manganese react with steam?

Answer 30

Manganese is above hydrogen in the reactivity series and so reacts with steam to give hydrogen and the metal oxide forming Manganese oxide

Question 31

Why does Iron rust?

Answer 31

Iron rusts in the presence of oxygen and water rusting occour with iron and the most common alloy of iron mild steel.

Rusting is a redox reaction iron ix oxidised

Question 32

How can rusting be prevented using Barriers?

Answer 32

Most common method to keep oxygen and water away from iron. Can do this by painting it coating it in oil in crease or covering with plastic. Coating iron with metal below in the reactivity series can be a barrier method.

Barrier methods are cheap ways of preventing rusting. Barrier methods have problems once the coating is broken, the iron underneath is exposed to oxygen and water and the iron rust.

Question 33

How can rusting be prevented using Galvanizing?

Answer 33

Galvanised iron is iron that is coated in a layer of zinc. As long as zinc is unscratched is servers as a barrier to air an water iron does not rust. even when scratched away it does not rust because zinc is more reactive than iron and so reacts with oxygen and water more rapidly than the iron does. Zinc corrodes instead of iron.

Question 34

How is Sacrificial Protection used to prevent rusting?

Answer 34

Zinc magnesium or aluminium blocks attacked to metal hulls prevent iron from rusting. Use metal more reactive than iron, more reactive metal reacts more readily in the presence of oxygen than the iron the corrosion of the more reactive metal stop iron from rusting. Replaced occasionally.