1reactivity series

Question 1

the chemistry of metals is studied

Answer 1

by analysing their reactions with water and acids

Question 2

reaction for calcium and water is

Answer 2

Ca (s) + 2H2O (l) ⟶ Ca(OH)2 (aq) + H2(g)

calcium + water ⟶ calcium hydroxide + hydrogen

Question 3

what metals on the reactivity series will react with dilute acids

Answer 3

above hydrogen

Question 4

the more reactive a metal is

Answer 4

the more vigorous the reaction will be

Question 5

metals such as potassium and sodium are

Answer 5

very dangerous and react explosively with acids

Question 6

when acids react with metals they form

Answer 6

a salt and hydrogen gas

Question 7

acid-metal reaction equation

Answer 7

metal + acid -> salt + hydrogen

Question 8

a more reactive metal will

Answer 8

displace a less reactive metal

Question 9

the reactivity of two metals can be compared using

Answer 9

the displacement reactions in salt solutions of one of the metals - this is easily seen as the more reactive metal slowly disappears from the solution, displacing the less reactive metal

Question 10

reactivity series

Answer 10

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

Question 11

rusting is

Answer 11

the chemical reaction between iron, water and oxygen to form hydrated iron(III) oxide

Question 12

what must be present for rust to occur

Answer 12

oxygen and water

Question 13

rusting is a

Answer 13

redox process and it occurs faster in salty water since the presence of sodium chloride speeds up the reaction

Question 14

rust equations

Answer 14

Iron + Water + Oxygen → Hydrated Iron(III) Oxide

4Fe (s) + 3O2 (g) + xH2O (l) → 2Fe2O3.xH2O (s)

Question 15

method to investigate rusting

Answer 15

Set up the apparatus as shown in the diagram
The water in the second test tube is boiled to remove any dissolved oxygen
The oil provides a barrier to prevent oxygen diffusing into the boiled water
Calcium chloride is a drying agent in the third test tube
Leave the apparatus for a few days to give it time to react

Question 16

results of investigating rusting

Answer 16

The nail on the left rusts as it is in contact with both air (which contains oxygen) and water
The nail in the middle does not rust as it is not in contact with air
The nail on the right does not rust as it is not in contact with water (calcium chloride absorbs any water molecules present due to moisture)
The results show that both air and water must be present for rusting to occur

Question 17

damage to iron structures

Answer 17

Rust is a soft solid substance that flakes off the surface of iron easily, exposing fresh iron below which then undergoes rusting
This means that over time all of the iron rusts and its structure becomes weakened

Question 18

barrier methods to prevent rusting

Answer 18

Rust can be prevented by coating iron with barriers that prevent the iron from coming into contact with water and oxygen- example is paint or grease
However, if the coatings are washed away or scratched, the iron is once again exposed to water and oxygen and will rust

Question 19

galvanising

Answer 19

the process where the iron to be protected is coated with a layer of zinc

Question 20

sacrificial corrosion

Answer 20

Sacrificial corrosion occurs when a more reactive metal is intentionally allowed to corrode
An example of this occurs with ships’ hulls which sometimes have large blocks of magnesium or magnesium alloys attached
The blocks slowly corrode and provide protection to the hull in the same way the zinc does by pushing electrons onto the iron which prevents it from being reduced to iron(III) ions

Question 21

oxidation

Answer 21

any reaction where the substance gains oxygen

Question 22

reduction

Answer 22

when a substance loses oxygen

Question 23

reducing agent

Answer 23

when something removes oxygen

Question 24

oxidising agent

Answer 24

when something supplies oxygen

Question 25

displacement reactions can be analysed in terms

Answer 25

redox reactions by studying the transfer of electrons

Question 26

method to investigate metals reacting with acids

Answer 26

Wear some safety glasses before handling acids
Using a small measuring cylinder, add 5 cm3 of dilute hydrochloric acid to each of three test tubes
Add about 1 cm length of magnesium ribbon to the first tube, observe and note down what you see
Use a lighted splint to test for any gases given off
To the second test tube add a few pieces of iron filings and to the third some zinc turnings
Observe what happens, test for any gases and note down your observations
Repeat the experiment with dilute sulfuric acid

Question 27

magnesium with dilute hydrochloric acid

Answer 27

Dissolves quickly, gets hot, gas given
off which goes pop with a lighted
splint, colourless solution left

Question 28

magnesium with dilute sulfuric acid

Answer 28

rapid bubbling, splint goes pop, metal dissolves

Question 29

iron with dilute hydrochloric acid

Answer 29

very slow bubbling

Question 30

iron with dilute sulfuric acid

Answer 30

slow reaction, small bubbles seen

Question 31

zinc with dilute hydrochloric acid

Answer 31

bubbles given off, metal slowly dissolving

Question 32

zinc with dilute sulfuric acid

Answer 32

metal dissolves forming a colourless solution, gas given off slowly

Question 33

magnesium with sulfuric acid equation

Answer 33

Mg + H2SO4 -> MgSO4 + H2

Question 34

magnesium with hydrochloric acid equation

Answer 34

Mg + 2HCl -> MgCl2 + H2

Question 35

zinc with sulfuric acid equation

Answer 35

Zn + H2SO4 -> ZnSO4 + H2

Question 36

zinc with hydrochloric acid equation

Answer 36

Zn + 2HCl -> ZnCl2 + H2

Question 37

iron with sulfuric acid equation

Answer 37

Fe + H2SO4 -> FeSO4 + H2

Question 38

iron with hydrochloric acid equation

Answer 38

Fe + 2HCl -> FeCl2 + H2

Question 39

conclusions of investigating metals reacting with acids

Answer 39

The metals can be ranked in reactivity order Mg > Zn > Fe
The three metals react in the same with both acids
Hydrogen and a metal salt solution is produced