15 — Reactivity series Flashcards

1
Q

Name the metals from most reactive to least reactive

A

Potassium
Sodium
Calcium
Magnesium
Aluminium
Carbon
Zinc
Iron
Tin
Lead
Hydrogen
Copper
Silver
Gold
Platinum

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2
Q

Name chemical reaction of reactive metals w cold water and state observations.

A

Metal + water -> metal hydroxide +. Hydrogen
Effervescence observed, metal dissolves

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3
Q

Name chemical reaction of metals w steam

A

Metal + steam -> metal oxide + Hydrogen
E.g. glass wool soaked in water heated strongly to generate a flow of stream over hot metal

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4
Q

Potassium reaction w cold water and steam

A

CW: Reacts v violently to form potassium oxide n hydrogen gas. Enuf heat is produced to cause h2 to catch fire n explodes.
S: reacts explosively.

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5
Q

Sodium reaction w cold water and steam

A

CW: Reacts violently to form NaOH and H2 gas. H2 may catch fire n explode.
S: React explosively.

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6
Q

Calcium reaction w cold water and steam

A

CW: Reacts readily to form Calcium hydroxide and hydrogen gas.
S: React explosively.

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7
Q

Magnesium reaction w cold water and steam

A

CW: Reacts v slowly w cold water w cold water to form magnesium hydroxide and hydrogen gas. A test tube of hydrogen gas is produced only after a few days.
S: hot magnesium reacts violently w steam to form magnesium oxide (white solid) n H2 gas. A bright white glow is produced during the reaction.

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8
Q

Zinc reaction w cold water and steam

A

CW: no reaction occurs
S: hot zinc reacts readily w steam to produce zinc oxide and H2 gas. Zinc oxide is yellow when hot and white when cold.

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9
Q

Iron reaction w cold water and steam

A

CW: no reaction
S: red-hot iron reacts slowly w steam to form iron oxide. Iron must be constantly heated for reaction to progress.

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10
Q

Lead, copper, silver reaction w cold water and steam

A

CW: no reaction
S: no reaction

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11
Q

State metals that can react w cold water

A

Potassium, Sodium, Calcium, Magnesium

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12
Q

State the metals that can react w steam

A

PSCMACZI

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13
Q

State reaction of metal w dilute hydrochloric acid and its observations

A

Metal +dilute HCl -> metal chloride + H2
Effervescence observed and metal dissolves

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14
Q

State reaction of metals w dilute HCl & observations

A

K, Na: react explosively
Ca: reacts violently
Mg: reacts rapidly
Zn: reacts moderately
Fe: Reacts slowly
Lead: reacts w HCl initially to form insoluble layer of Lead(II) Chloride, which coats the lead and prevents further reaction from taking place
Copper, silver: no reaction

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15
Q

Reaction of metal oxides w carbon

A

Metal oxide + carbon (reducing agent) -heat> metal + CO2
The lower the metal is in the reactivity series from Carbon, the easier the reduction of metal oxide occurs. Anything above Carbon, no reaction occurs.

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16
Q

Reaction of metal oxides w H2

A

Metal oxide + H2 (reducing agent) -heat> metal + steam

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17
Q

State reduction of different metal oxides by carbon and H2.

A

C: PSCM not reduced
H2: PSCM not reduced

C: Zn oxides require highest tempt for reduction. Carbon will reduce the oxide of Zn.
H2: not reduced

C: Iron reduced
H2: iron oxides require highest tempt for reduction

C: LSG reduced
H2: LSG reduced

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18
Q

Displacement reaction of metals

A

metal a which is more reactive than metal b has a higher tendency to lose electrons to form positive ions. Thus, metal a will displace metal b from metal compound solution.

Note: displacement is metal displacing metal from aq solution.

19
Q

Displacement of metals in redox.

A

A in x is oxidised as oxidation state of A increases from _ in Acompound to _ in Bcompound. C in y is reduced as oxidation states of C decreases from _ in _ to _ in _. Since oxidation and reduction occurs simultaneously, this is a redox reaction.

20
Q

Reaction betw metal n metal oxide

A

More reactive metal can reduce oxide of a less reactive metal

21
Q

Action of heat on metal carbonates

A

More reactive the metal, more thermally stable the metal carbonate hence the more difficult it is to decompose carbonate by heat.

PS: unaffected by heat
CMACZILC: decomposes into metal oxide n CO2 on heating. Gas evolved forms white ppt. In limewater.
Silver: decomposes into silver + CO2. Silver oxide produced is thermally unstable n will further decompose to form silver.

22
Q

Ore definition and state 2 main methods for extracting metals from ore

A

An ore is a compound of the metal mixed w large amounts of earth and rock. (usually oxides, sulfides, chlorides and carbonates)

Reducing metal compound (ore) to metal by carbon.
Electrolysis.

23
Q

Metals and their methods of extractions

A

PSCM: electrolysis
Zn n anything below carbon: reduction w carbon

24
Q

Rusting definition

A

Rusting or the corrosion of iron is the slow oxidation of iron to form hydrated iron (III) oxide, rust.

25
Q

Conditions needed for rusting

A

Both oxygen and water needed
Acidic substances speed up rate of rusting.

26
Q

Protection against rusting

A

Barrier protection:
_ acts as a protective barrier that prevents iron/iron in steel from coming into contact w oxygen n water by coating a layer around iron, thus preventing rusting from occur.
- painting
- oiling or greasing
- plastic coating
- tin-plating
- chrome-plating

Sacrificial protection:
Galvanising: Zn is a more reactive metal than iron thus has a higher tendency of losing electrons, corroding in place of iron, acting as a sacrificial metal hence preventing iron from rusting.
Attaching metal blocks of Zn or mg: Zn/Mg is a more reactive metal than iron thus has a higher tendency of losing electrons, corroding in place of iron, acting as a sacrificial metal hence preventing iron from rusting.

27
Q

Corrosion of other metals other than iron

A

Other metals require water and oxygen to corrode. However, oxide layer forms a protective coating thus preventing further reaction.

28
Q

Suggest why oil and paint r not suitable for use on underground pipes

A

Oil and paint can be easily damaged/worn off; it is difficult to repaint the pipes n iron in steel pipes will rust when exposed to oxygen and water.

29
Q

Determining reactivity of metal thru thermal stability of metal carbonates

A

Heat the metal carbonate -> bubble gas produced in limewater -> record time taken for white ppt to form in limewater. Longest time for white ppt to form is most reactive metal.
Explain: higher the reactivity -> more thermal stable the metal carbonate -> longer time taken for compound to break down into constituent elements

30
Q

Using ideas about the arrangement of atoms, explain why carbon steels r preferred over iron

A

Carbon steels contain atoms of different sizes that disrupts the orderly arrangement of atoms in pure metal. Thus layers of atoms cannot slide over each other easily, making carbon steels harder.

31
Q

Why electrolysis is expensive

A
  • high operating tempt -> more energy needed to heat metal
  • additional energy required to remove impurities during electrolysis
  • hence recycling is promoted -> Conserve finite natural resources + reduce waste produced
32
Q

CAQ:H2 gas passed over copper (II) oxide and MgO

A

Black copper (II) oxide -> turns reddish brown. H is more reactive than copper hence displaces copper from copper (II) oxide.

However, magnesium oxide remains white, with no observable change, since Mg is more reactive than H -> no displacement occurs.

33
Q

Describe similarities and differences betw what happens during displacement of copper and bromine.

A

Both involves redox reactions
Colour change occurs during both displacement reactions.
Copper reduced but bromine oxidised.
Solid formed in copper displacement but aqueous solution of bromine formed in bromine displacement.

34
Q

Relationship betw reactivity of halogen and rate of breakdown oftheir compound

A

Reactivity decreases down Group VII from chlorine, bromine, to iodine. As reactivity decreases, the compound breaks down faster to form grey silver metal on standing.
(Halogen r metal compounds from group VII)

35
Q

Suggest why helium cannot be recovered if it is released into the atmosphere

A

Helium is a noble gas that is chemically unreactive and hence monoatomic. Thus, it cannot react with any substance to form a compound that can be easily recovered.

36
Q

Oxyanion

A

A negatively charged ion that contains oxygen.

37
Q

Explain why lead reacts with nitric acid but gold does not.

A

Lead is above hydrogen in the reactivity series, while gold is below hydrogen. This means that lead is more reactive and loses electrons more readily to form lead(II) ions.

38
Q

Describe the trend in reactivity down Group I and Group VII.

A

Reactivity increases down Group I, but decreases down Group VII.

39
Q

Which metal and which metal oxide are most likely to react together to give the most vigorous reaction?

A

Most reactive metal in the list + least reactive (least stable and hence most reactive) metal oxide.

40
Q

The student decides to investigate the thermal stability of the carbonates of the 4 metals. He heats each metal carbonate in a test tube and bubbles gas given off through limewater. Describe what results he should record.

A

Time taken for white precipitate to form in limewater.

41
Q

The student decides to investigate the thermal stability of the carbonates of the 4 metals. He heats each metal carbonate in a test tube and bubbles gas given off through limewater. Describe how he can se his results to place the metal carbonates in order of thermal stability.

A

The longer the time taken for white precipitate to form, the more thermally stable the metal carbonate and hence the more reactive the metal.

42
Q

How limiting reactant affects tempt

A

As the volume of P^, change in tempt ^. As CuSO4 is the limiting reactant, when a larger vol of CuSO4 is used, more products r formed resulting in more thermal energy released.

43
Q

If experiment was repeated using an excess of iron powder instead of zinc powder, predict the effect on changes in tempt.

A

Change in tempt will be lower than when Zn was used. Iron is less reactive than Zn hence less thermal energy is released when iron is used.