Metal reactivity And Extraction

Question 1

What happens when metals react with water?

Answer 1

metal + water —-> metal hydroxide (alkali) + hydrogen

Question 2

What happens when metals react with oxygen?

Answer 2

metal + oxygen —> metal oxide

Question 3

Which part of the periodic table do the more reactive metals come from?

Answer 3

group 1/group 2

Question 4

The metals appear to get heavier when they react with oxygen. Explain why

Answer 4

Oxygen molecules from the air react with the metal, adding mass to form a metal oxide.

Question 5

many metals react with acids, when this happens the metal fizzes as bubbles are produced -what do these bubbles mean?

Answer 5

a gas (hydrogen) is produced

Question 6

how can you test if the gas produced is hydrogen

Answer 6

place a burning splint next to the mouth of the test tube, a ‘squeaky pop’ as the gas ignites shows that hydrogen is produced

Question 7

What happens when metals react with acids?

Answer 7

metal + acid —> salt + hydrogen (e.g. magnesium + nitric acid —-> magnesium nitrate + hydrogen)

Question 8

displacement reaction

Answer 8

a more reactive metal replaces/displaces a less reactive metal in a compound

Question 9

What are 2 signs that may indicate a displacement has occurred?

Answer 9

-colour change
-precipitate forms (solid appears in a solution)

Question 10

What’s the order of the first 5 elements in the reactivity series?

Answer 10

Potassium, Sodium, Calcium, Magnesium, Aluminium

Question 11

what is oxidation

Answer 11

loss of electrons/gain of oxygen

Question 12

what is reduction

Answer 12

gain of electrons/loss of oxygen

Question 13

Why is aluminium (and other very reactive metals) extracted using electrolysis?

Answer 13

It’s more reactive than carbon and can’t be displaced by it, so electrolysis is used instead

Question 14

Why are alloys stronger than pure metals?

Answer 14

Different sized atoms distort the layers, preventing the atoms from sliding over each other

Question 15

what is a redox reaction

Answer 15

both oxidation and reduction occur in the same reaction

Question 16

what is an ore

Answer 16

a rock that contains enough of a metal or metal compound to make extracting the metal worthwhile

Question 17

Why don’t metals like gold and platinum need to be extracted?

Answer 17

they are highly unreactive so are found uncombined and do not need to be extracted

Question 18

what is a ion

Answer 18

electrically charged atom/element

Question 19

what is electrolysis

Answer 19

process by which ionic substances are decomposed (broken down) into simpler substances when an electric current is passed through them

Question 20

Give an example of an alloy and its use

Answer 20

bronze - statues and medals, brass - musical instruments

Question 21

pure metals properties

Answer 21

malleable, soft (can bend), conduct electricity

Question 22

alloys properties

Answer 22

harder, Layers disrupted → stronger

Question 23

what is a bauxite

Answer 23

Bauxite is the ore that contains aluminium oxide, used to extract aluminium.

Question 24

how is aluminium oxide isolated from bauxite

Answer 24

purify bauxite to get aluminium oxide powder

Question 25

Why does cryolite need to be added to aluminium oxide before the extraction of pure aluminium?

Answer 25

Cryolite lowers the melting point of aluminium oxide, which reduces the energy needed and makes the process cheaper and more efficient.

Question 26

In the electrolysis of aluminium oxide, what species goes to the anode and what goes to the cathode?

Answer 26

-Aluminium ions (Al³⁺) go to the cathode. -Oxide ions (O²⁻) go to the anode.

Question 27

Write a definition on an alloy.

Answer 27

mixtures of two or more metals, or a mixture of metals and non-metals

Question 28

explain how aluminium is extracted

Answer 28

-Aluminium can be extracted using electrolysis. -Bauxite is first purified to produce aluminium oxide, Al2O3 -Aluminium oxide is then dissolved in molten cryolite mixture - which lowers the melting point -When an electric current is passed through an ionic compound, the compound breaks down into its ions, thereby becoming an conducting liquid when in an aqueous solution. -When a current passes through aluminium oxide, aluminium is oxidised and oxygen is reduced. -symbol equation: Al2O3 ---> 2Al3+ + 3O2- -The oxidised aluminium gets attracted to the cathode and the reduced oxygen gets attracted to the anode. -Aluminium can then be extracted from the cathode and oxygen reacts with carbon to produce carbon dioxide, which bubbles out of the solution.

Question 29

what are electrolytes

Answer 29

liquid containing ions

Question 30

reaction that occurs in cathode

Answer 30

al3+ + 3e- ---> al (Aluminium ions gain electrons - reduced)

Question 31

reaction that occurs in anode

Answer 31

2O2- ---> O2 + 4e- (O2- is oxidised - lost electrons)

Question 32

how is copper extracted

Answer 32

Copper is extracted from copper oxide by heating it with carbon in a reduction reaction. This works because carbon is more reactive than copper, so it can remove the oxygen from copper oxide. The word equation for the reaction is: Copper oxide + carbon → copper + carbon dioxide

Question 33

what is the reactivity series

Answer 33

The reactivity series is a list of metals (and sometimes non-metals) arranged in order of their chemical reactivity, from most reactive to least reactive.

Answer 34

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