metals

Question 1

what type of surfaces do metals have?

Answer 1

shiny surfaces

Question 2

why do metals have high melting points and boiling points?

Answer 2

large amount of energy required to overcome the strong electrostatic forces of attraction between the positive ions and sea of delocalised electrons

Question 3

why are metals good conductors of electricity?

Answer 3

delocalised electrons can move freely to act as mobile charge carriers to conduct electricity

Question 4

why are metals good conductors of heat?

Answer 4

delocalised electrons can move freely to transfer heat from one point to another quickly as the electrons gain energy and move faster

Question 5

why are metals malleable/ductile?

Answer 5

pure metals tend to be soft as they are arranged in orderly manner which can slide across each other easily

Question 6

why do metals have high density?

Answer 6

atoms are closely packed together in a given volume

Question 7

what is an alloy?

Answer 7

a mixture of a metal with one or a few other elements

Question 8

why are alloys stronger and harder than the constituent pure metal?

Answer 8

pure metal consists of atoms of the same size which are arranged in an oderly manner. when a force is applied, the layers of atoms can slide across each other easily, in an alloy, the different size of atoms from other elements disrupts the orderly arrangement of atoms, preventing the layers of atoms from sliuding over each other easily.

Question 9

what is the metal reactivity series?

Answer 9

potassium, sodium, calcium, magnesium, aluminium, zinc, iron, lead, (hydrogen), copper, silver, gold

Question 10

what do reactive metals do?

Answer 10

lose electrons to form positive ions + react vigorously to form compound + have vigorrous effervesence in chemical reactions + corrode easdily when exposed to moist air/oxygen

Question 11

why are reactive metals good reducing agents?

Answer 11

since reactive metals tend to lose electrons, it tends to oxidise itself

Question 12

how do more reactive metals react with water?

Answer 12

metal + water -> metal hydroxide + hydrogen

Question 13

how do less reactive metals react with steam?

Answer 13

metal + steam -> metal oxide + hydrogen

Question 14

how does potassium react with cold water?

Answer 14

it reacts very vigorously with cold water, lilac flame observed, enough heat is produced to cause hydrogen gas to ignite and explode

Question 15

how does sodium react with cold water?

Answer 15

react vigorously with cold water, hydrogen gas may ignite and catch fire, yellow flame observed

Question 16

how does calcium react with cold water?

Answer 16

reacts quickly/readily with cold water

Question 17

how does magnesium react with cold water?

Answer 17

reacts very slowly with cold water

Question 18

how does aluminium/zinc/iron/lead/copper/silver/gold react with cold water?

Answer 18

no visible change

Question 19

how does potassium/sodium/calcium react with steam?

Answer 19

reacts violently and explosively with steam

Question 20

how does magnesium react with steam?

Answer 20

hot magnesium reacts vigorously with steam to produce a bright white glow, white solid formed

Question 21

how does zinc react with steam?

Answer 21

hot zinc reacts readily with steam, yellow solid formed which turns white when cooled

Question 22

how does iron react with steam?

Answer 22

hot iron reacts slowly with steam to form a black solid,

Question 23

how does lead/copper/silver/gold react with steam?

Answer 23

no visible change with steam

Question 24

how does potassium/sodium react with acid?

Answer 24

react violently and explosively with acid, effervesecne of colourless gas

Question 25

how does calciumj react with acid?

Answer 25

reacts vigorously with acid, effervesence of colourless gas observed

Question 26

how does magnesium react with acid?

Answer 26

reacts rapidly with acid, effersvesence of colourless gas

Question 27

how does zinc react with acid?

Answer 27

reacts moderately fast withh acid, effervesence of colourless gas observed

Question 28

how does iron react with acid?

Answer 28

reacts slowly with acid, slight effervesence of colourless gas

Question 29

how does lead react with acid?

Answer 29

reacts very slowly with acid, no appparent reaction

Question 30

how does copper/silver/gold react with acid?

Answer 30

no visible change with dilute hydrochloric acid

Question 31

why does aluminium not seem react with cold water, steam or acid?

Answer 31

exposed aluminium reacts readily with oxygen in the air to form an inert aluminium oxide layer that protects protects aluminium metal from further reaction with cold water, steam or acid

Question 32

how do displacement reactions work?

Answer 32

a more reactive metal displaces a less reactive metal from its salt solution

Question 33

why is the less reactive metal displaced?

Answer 33

the more reactive metal has a higher tendency to lose electrons to form positive ions, compared to the less reactive metal

Question 34

what happens when a zinc metal strip is dipped into copper (II) sulfate solution?

Answer 34

blue copper sulfate solution fades to colourless + pink or reddish brown solid is deposited on zinc metal strip + zinc metal strip dissolves gradually and decreases in size

Question 35

why does get copper displace when a zinc metal strip is dipped into copper (II) sulfate solution?

Answer 35

zinc is more reactive than copper, hence zinc displaces copper from copper (II) sulfate solution, forming zinc sulfate solution and coper metal

Question 36

why is there no visible reaction when iron filings are added to a magnesium sulfate solution?

Answer 36

iron is less reactive than magnesium and it cannot displace magnesium from magnesium sulfate

Question 37

why will the mixture of zinc metal and copper oxide turn into a reddish-brown solid and a yellow solid that turns white after cooling?

Answer 37

zinc is more reactive than copper and will displace copper (II) oxide, producing copper metal and zinc oxide which is yellow when hot and white when cooled

Question 38

what is the general reaction for the reduction of a metal oxide?

Answer 38

oxide of metal x + reducing agent --- (reduction) --> metal X

Question 39

which metal oxides are not reduced upon heating with either carbon or hydrogen?

Answer 39

potassium, sodium, calcium, magnesium, aluminium

Question 40

how are metal oxides reduced by carbon?

Answer 40

metal oxide + carbon -> metal + carbon dioxide

Question 41

how are metal oxides reduced by hydrogen?

Answer 41

metal oxide + hydrogen -> metal + steam

Question 42

which metal oxides are reduced to metal upon heating with carbon, with increasing ease down the series?

Answer 42

zinc, iron, lead, copper

Question 43

which metal oxide is reduced by heating alone?

Answer 43

silver

Question 44

which metal oxide is not reduced to metal upon heating with hydrogen?

Answer 44

zinc

Question 45

which metal oxide is reduced to metal upon heating with hydrogen with increasing ease down the series?

Answer 45

iron, lead, copper, silver

Question 46

what are common reducing agents used to reduce metals?

Answer 46

carbon. carbon monoxide, hydrogen

Question 47

what is the general reaction when metal carbonates are heated strongly?

Answer 47

metal carbonate -(heat)-> metal oxide + carbon dioxide

Question 48

what does thermal decomposition mean?

Answer 48

a compound breaking down to simpler substances upon heating

Question 49

`what is the relationship between the metal reactivity series and its ease to decompose when heated?

Answer 49

the lower the position of a metal in the reactivity series, the easier it is for the metal carbonate to decompose when heated d

Question 50

why is it more difficult to decompose a reactive metals' carbonate?

Answer 50

the more reactive the metal is, the more thermally stable the metal compound is

Question 51

which metals carbonates are stable to heating?

Answer 51

potassium, sodium

Question 52

which metal carbonates decompose to metal oxide and carbon dioxide with increasing ease down the series?

Answer 52

Ca, Mg, Al, Zn, Fe, Pb, Cu

Question 53

which metal carbonate decomposes into its metal +carbon dioxide + oxygen on heating?

Answer 53

silver

Question 54

what is the relationship between metal reactivity and the extraction method from its ores?

Answer 54

the more reactive the metal is, the more energy is required to break the strong bonds and extract the metal from the metal ore

Question 55

which metals have to be extracted via electrolysis?

Answer 55

potassium, sodium, calcium, magnesium, aluminium

Question 56

why can only certain metals be extracted via electrolysis?

Answer 56

very reactive metals form stable compounds with strong bonds, hence their compounds require a lot of energy to break down and can only be extracted by using electrolysis

Question 57

which metals are extracted via reduction with carbon or carbon monoxide?

Answer 57

moderately reactive metals from compounds that can be reduced to metal by reacting with carbon

Question 58

why can only certain metals be extracted via reduction with carbon/carbon monoxide?

Answer 58

metals above carbon cannot be extracted by reduction with carbon

Question 59

which metals occur naturally uncombined?

Answer 59

silver, gold

Question 60

why do unreactive metals occur naturally uncombined?

Answer 60

unreactive metals do not form compounds easily

Question 61

what is added into the top of the blast furnace?

Answer 61

haematite, coke and limestone

Question 62

why is coke added into the furnace?

Answer 62

it has a high carbon content and has little impurities and produces carbon monoxide which will reduce iron (III) oxide

Question 63

what happens to the coke in a blast furnace?

Answer 63

it reacts with oxygen from the hot air blown in through the bottom of the furnace to form carbon dioxide

Question 64

what happens to the carbon dioxide in a blast furnace?

Answer 64

it reacts with coke to form carbon monoxide

Question 65

what does the carbon monoxide do in the blast furnace?

Answer 65

it reduces the iron (III) oxide in haematite to form molten iron and carbon dioxide

Question 66

what is the purpose of limestone in the blast furnace?

Answer 66

to remove acidic impurities

Question 67

what happens to the molten iron in the blast furnace?

Answer 67

it sinks to the bottom of the furnace and carbon dioxide escapes as hot waste gases