Metals and Redox Flashcards
What makes a metal more or most reactive?
If it can easily give away it’s outer shell elctrons
What method of extraction is used for all metals more reactive than zinc?
Electrolysis
How is zinc and iron extracted?
By reducing them with carbon (carbon is more reactive)
How is copper extracted?
By being reduced with either of the more reactive non-metals hydrogen and carbon
What is the term used to define metals which are found naturally in the ground as they are unreactive?
Native
What are the two native metals in the reactivity series?
Silver and gold
How are metals which aren’t native found as?
Compounds which are called ores
What is an ore?
A metal compound dug out of the ground which is economically worth extracting
What is the colour and name of copper carbonate ore?
Green compound called Malachite
What is the first stage of extracting copper from copper carbonate?
Thermal decomposition
What are the products and reactants of thermal decomposition of copper carbonate?
Reactants: Copper carbonate (CuCO3)
Products: Copper oxide (CuO) and carbon dioxide(CO2)
What is the second stage of extracting copper from copper carbonate?
Reacting the copper oxide with carbon to get copper and carbon dioxide
What is reduction?
The loss of oxygen from one reactant or the gain of electrons
What is oxidation?
The gain of oxygen or the loss of electrons
What is the name of the ore and chemical symbol of Aluminium Oxide?
- Bauxite
- Al2O3
How is aluminium extracted from bauxite?
Using electrolysis
How is aluminium oxide made into an electrolyte for electrolysis?
It is melted until it is molten and is dissolved in cryolyte to lower it’s melting point in the first place
During the electrolysis of aluminium oxide, what product is made at the cathode?
Pure aluminum
During the electrolysis of aluminium oxide, what product is made at the anode? Why?
Carbon dioxide because oxygen reacts with the carbon anode to make carbon dioxide
What kind of structure does a metal have?
A giant metallic structure
What kind of bonding does a metal have?
Metallic bonding
Define metallic bonding:
The electrostatic attraction between positive ions and delocalised electrons in a layered structure
What are the general physical properties of metals?
- High metling point
- Ductile (can be drawn into wires)
- Malleable (can be shaped)
- Good conductor of electricity
- Good conductor of heat
Why do metals (transition) generally have a high melting point?
Because there are strong metallic bonds which take a lot of energy to break
Why are metals generally ductile?
The layers of positive ions can slide past eachother when a force is applied
Why are metals generally malleable?
The layers of positive ions can slide past eachother when a force is applied
Why are metals generally good conductors of heat?
The delocalised electrons in the metal can transfer the heat effectively
Why are metals generally good conductors of electricity?
The delocalised electrons can carry the electric charge through the metal
What are the similar physical properties of alkali metals and transition metals?
- Good conductors of heat and electricity
- Malleable and Ductile
- Shiny
What are the different physical properties of alkali metals and transition metals?
- Alkali metals have lower density (float on water)
- Alkali metals are softer (cut easily)
- Alkali metals aren’t as strong as transition metals
- Alkalis have lower melting and boiling points
What are the products when a metal and oxygen react?
A metal oxide
What are the products when a metal and acid react?
A metal salt and hydrogen
What are the products when a metal and water react?
A metal hydroxide and hydrogen
What kind of compounds do alkali metals form?
White compounds
What is the only oxidation number for any alkali metal?
+1
Can alkali metals be used as catalysts?
No
How do alkalis react in water typically?
Violently
What kind of compounds do transition metals form?
Coloured compounds
How do transition metals react with water?
Fairly unreactive ie. Copper does not react with water
Can transition metals be used as catalysts>
Yes ie. Fe used to make ammonia and Nickel used to harden margarine
How do potassium, sodium, lithium and calcium react with O2?
Very quickly (they tarnish) so they must be stored in oil
How do potassium, sodium, lithium and calcium react with water?
All produce gas, potassium produces lilac flame, float and move on surface and eventually dissolve
How do potassium, sodium, lithium and calcium react with acid?
explosive
How does magnesium react with oxygen?
Very slowly if at all (tinges of tarnishing)
How does magnesium react with water?
Very slowly
How does magnesium react with acid?
Quickly and fairly violent. Lots of gas is produced
How do iron and zinc and copper react with oxygen?
Very very slow (no visible observations really)
How do iron and zinc and copper react with water?
Iron slowly rusts but the other two have no reaction
How do iron and zinc and copper react with acid?
Slowly , bubbles form on the surface
What gas is given off during the metal s reacting with water and acid?
Hydrogen
What is the test for hydrogen?
Squeaky pop with a lighted splint
What is a displacement reaction?
When a more reactive metal displaces a less reactive metal from its compound
What are the ions in a redox reaction called if they don’t take part in the reaction?
Spectator ions
What is an alloy?
A mixture of a metal and either a non-metal or an additional metal
What makes a metal an element?
When there is only one type of ato making it up
Why are alloys stronger than pure metals?
The atoms in them are different sizes so layers cannot easily slide past eachother
What is low carbon steel composed of and used for due to its property?
Iron with 0.1%-0.3% of carbon
It is easily shaped so is ideal for car bodies
What is high carbon steel composed of and used for due to its properties?
Iron with 0.22%-0.25% of carbon
Very strong, inflexible, brittle so used for blades for cutting tools and even bridges
What is low stainless steel composed of and used for due to its properties?
Iron with added chromium and nickel
Corrosion resistant and hard so used for medical equipment, cutlery and corrosive substance containers
What is brass composed of and used for due to its property?
70% Copper and 30% Zinc
Low friction so used for moving parts such as taps, door fittings and musical instruments
What is bronze composed of and used for due to its property?
95% Copper and 5% Tin
Harder than copper so used for statues. church bells and medals
What is gold composed of and used for due to its property?
Gold with copper, zinc or silver
24 carat is soft so used in jewellery
9 carat is used in dental fillings and electronic devices due to low resistance and high conductivity
What is aluminium composed of and used for due to its property?
Aluminium with other metals such as magnesium
Low density and soft and conductive so alloyed to make stronger for aircrafts and electric pylon wores
Why does aluminum not corrode?
It has a layer of aluminum oxide on it’s surface
What is corrosion?
The destruction of materials by chemical reactions with substances in the environment
Rust is a form of corrosion which only occurs with iron, what is its chemical name and symbol?
A hydrated iron oxide - Fe2O3.H2O
Why does all pure iron with water eventually corrode away?
The rust gets on the surface of the iron but is soft and crumbly so flakes off leaving more of the surface of the iron to rust.
What are the conditions which are required for iron to rust?
Water and air
What are in the three test tubes used to set up the different conditions for iron to see under which ones it rusts?
- Test tube with iron and anhydrous calcium oxide which absorbs moisture
- Test tube with boiled water (removes oxygen) and oil (prevents re-entry of oxygen) with iron
- Test tube with half air and water for nail
How coukd you tell rust is present on the iron in the test tube with water and air?
Because the mass of the nail increases as the iron atoms chemically bond to the oxygen and water molecules creating a new compound
What are the methods to prevent corrosion?
- Coating to create a barrier (e.g. greasing, painting)
- Cover in plastic
- Electroplating
- Sacrificial protection
- Galvanising
How does sacrificial protection prevent the desired metal from corroding?
The more reactive metal attached to the desired metal corrodes in its place
How does galvanising prevent the desired metal from corroding?
The desired metal’s surface is covered so there is a barrier but it is covered with a meterial which if scratched, will corrode in place of the desired metal as sacrifical protection (used in “tin cans”)
Why do electrons become delocalised in metals?
Because the electron orbitals in metal atoms overlap.
What is a pure compound?
A coumpound made of one substance without any mixtures
