Metals And Reactivity Series Flashcards
Reactions of Na and K when left in air
These soft metals can be cut easily with knife to give a shiny surface which quickly tarnishes
Reactions of K and Na when heated in air
Burns with a lilac flame, forming a white solid
Burns with a yellow/orange flame, forming a white solid
Reactions of Ca, Mg, Al, Zn when left in air
Reacts slowly with the air forming a layer of oxide
Ca when heated in air
Burns with a brick red flame, leaving a white solid
Mg reacted when heated in air
Burns with a bright white flame leaving a white ash
Al reaction when heated in air
Sheets of aluminium do not burn easily. Powdered aluminium burns with white peaks leaving a white solid
Zn reaction when heated in air
Burns steadily, forming a yellow solid which when cooled changes to white
Reactions Fe and Cu when left in air
Oxide layer is easily rubbed off
Fe heated in air
Sheets of iron do not burn easily. Iron wool or iron filings burn with yellow/orange sparks forming a black solid
Cu heated in air
Sheets of red brown copper glows red and forms a black layer of copper oxide but does not burn. There may be a blue - green flame observed
Na reaction with water
Floats, moves rapidly around the surface. So much heat is released that Na melts and forms a sphere of molten metal
General equation for metal and water
Metal + water —> metal hydroxide + hydrogen
K reaction with water
Floats, moves rapidly around the surface. Bursts into lilac flame. Bubbles of gas released. Colourless solution formed. Heat is released. Potassium disappears at the end.
Further tests for K
Solution changes Universal Indicator from green to blue.
Ca reaction with water
Ca granules will sink initially then rises. Bubbles of gas evolved. Beaker feels warm to the touch as heat is evolved. Calcium disappears. Colourless solution with a white ppt (due to Ca(OH)2 which is only slightly soluble).
Mg reaction with water
Very few bubbles are observed even after leaving for several days.
Al, Fe, Zn and Cu reaction with water
No reaction
Iron will rust after a few days
General equation for reaction between water and metal
METAL + WATER —>METAL HYDROXIDE + HYDROGEN
Mg reaction with steam
Reacts when heated. Produces a very bright white light. Heat given out. A white powder remains.
Al reaction with steam
Aluminium foil will not react. Small pieces will react when the oxide layer is taken off. Aluminium powder reacts when heated to form a white powder. Heat is given out.
Zn reaction with steam
Reacts when heated. Glows as steam is passed over producing a yellow powder. Heat is given out. Yellow powder becomes white when it is left to cool.
Fe reaction with steam
Iron must be heated until it glows red before the steam is passed over. Reacts to form a black solid.
General equation for metal and steam
METAL + STEAM —> METAL OXIDE + HYDROGEN
Does copper react with water or steam?
Copper does not react with cold water or steam. It is used in plumbing.
Also metals below copper in the reactivity series, for example, silver and gold do not react with cold water or steam.
Mnemonic for reactivity series
Please - K Send- Na Little - Li Charlie's - Ca Monkeys - Mg And - Al Coloured - C Zebras - Zinc In - Fe Tin - Sn Cages - Cu Securely - Ag Guarded - Au
Write the half equation for this :
Symbol equation Zn + 2HCl —> ZnCl2 + H2
Zn —> Zn 2+ + 2e-
Write the half equation for this
Symbol equation 2Mg + O2 —> 2MgO
Mg —> Mg 2+ + 2e-
Explain what happens to the calcium atoms in the reaction of water and metal in terms
of electrons.
The calcium atoms lose electrons
Write half equations for sodium and potassium
Na—> Na+ +e-
K —> K+ +e-
Define a displacement reaction
A displacement reaction is one where a more reactive element displaces a less reactive element from its compound.
Describe the beginning and end of an experiment using copper and silver nitrate
Beginning - Orange-brown copper wire placed in colourless solution.
End - The solution turns blue and the copper wire is coated with silver crystals.
Describe the colour changes in these displacement reactions
magnesium + copper (II) sulfate
magnesium + iron (II) sulfate
iron + zinc sulfate
iron + copper (II) sulfate
zinc + copper(II) sulfate
zinc + magnesium sulfate
blue solution turned colourless and a
solid formed.
pale green solution turned colourless and a
solid formed
no reaction
blue solution went pale green and a solid
formed.
blue solution turned colourless and a
solid formed.
no reaction
Which one of the four metals above forms a black layer of metal oxide when it is strongly heated in the air?
Copper forms a black layer of copper oxide when it is strongly heated in the air.
Define ore
Definition : An ore is a rock that contains a metal compound from which the metal can be extracted.
Two methods of extraction to obtain metals from ores:
Electrolysis
Reduction using carbon
Define phytomining
Phytomining is the use of plants to absorb metal compounds from soil as part of metal extraction.
Describe the process of phytomining (6)
- Some plants such as rapeseed are very good at absorbing metal compounds from the ground through their roots.
- These plants are grown on ground that contains low-grade ores, and so the metal is removed from the ore and enters the plant.
- The plants are harvested, dried and then burned to produce an ash, which is rich in metal compounds.
- An acid such as sulfuric acid is added to the ash and insoluble metal compounds react to produce a solution containing soluble copper compounds.
- The solution is called a ‘leachate’.
- The metal can then be obtained by adding scrap iron to the leachate solution, and a displacement reaction will occur
What is the solution containing soluble metal compounds produced from phytomining called?
leachate
Name two disadvantages for traditional methods
Traditional methods involve digging, moving and disposing of large quantities of rock.
- This involves noise and dust pollution, and uses large amounts of energy to move and transport the rock.
Explain how the reactivity of metals is related to the tendency of a metal to form its positive ion
The reactivity of a metal depends on the tendency of the metal to lose outer shell electrons and form its positive ion
The greater the tendency to lose outer shell electrons the more reactive the metal
explain and describe the displacement reactions of metals with other metal ions in solution (4)
- When solid Metal compounds are heated with a solid metal, a displacement reaction can occur
- This is a redox reaction
- They are carried out in a crucible where both the metal and metal oxide are in powder form to increase contact between them
- The further apart the metals in the reactivity series the faster and more exothermic the reaction
How are metals high in the reactivity series extracted from metal ores ?
Metals high in the reactivity series are extracted by electrolysis
How are metals low in the reactivity series removed from their ores ?
Reduction with carbon or carbon monoxide
Which metals are extracted by electrolysis
Aluminium and metals above it
Equation for reaction between scrap iron and copper ii Sulfate
Fe + CuSO4 —> FeSO4 + Cu
Two advantages to phytomining
- Its less destructive than traditional mining methods
- Carbon dioxide is absorbed as the plants grow
Disadvantages of phytomining (2)
- It is a slow process – time is needed for plants to grow
- Less Copper is extracted
How must sodium, potassium and calcium be heated in air?
Under very careful supervision. Reactions can be dangerous
