Flashcards in Unit 3.1 - Chemistry In Society/metals Deck (58):
When do metallic bonds occur?
Metallic bonds occurs between the atoms of metal elements
What are outer electrons?
Delocalised/free to move
What does outer electrons being delocalised produce?
An electrostatic force of attraction between the positive metal ions (atoms that have lost an electron to become positively charged)
What does the negitive delocalised electrons act as?
A glue, holding atoms together
What is the reason for metals being conductors of electricity?
The delocalised electrons
What must happen in order for a substance to conduct electricity?
It must allow electrons to flow through it (metals do this well)
What happens as one electron moves into the metal from the power supply?
Another electron will jump off the metal
Will the metal be changed throughout the conduction of electricity?
No, the metal will remain completely unchanged throughout this and it will always have the same number of electrons
Why do Gold, silver and platinum not react with water?
They are all unreactive metals
What can explode in water?
What metals react strongly with water?
The alkali metals, lithium, sodium and potassium
What reacts more with acids?
The more reactive metals
What reacts more with water?
The more reactive metals
What metals will react with and acid and why?
Only metals above hydrogen in the reactivity series will react with acid because all acids contain H+ ions.
What metals does acid not have an affect on?
Gold and Platinum
Metal + Acid = Salt + Hydrogen
Magnesium + Hydrochloric acid
Equation - Mg(S) +2HCL(aq)=MgCl2(a)+H2(g)
Reactions with Oxygen
Metal +oxygen =metal oxide
Magnesium reacting with Oxygen to give off a bright light and a exothermic reaction
Why do the reactions of metals make them very useful?
Their use in batteries which provide electricity for our use
What is electricity?
Electricity is a flow of electrons that travel along wires
How is electricity produced in a battery?
By a chemical reaction taking place in the battery
Why do batteries eventually run out?
Because eventually the chemicals in batteries are used up
What is the Reactivity series?
A list of elements, listed in order of reactivity starting with the most reactive.
The reactivity series
Most reactive - Potassium
Least reactive - Platinum
Magnesium and copper are cowboys in the old wild west. To win the heart of a fair lady they challenge each other to a shoot out at high noon. They meet at noon stand back to back walk twelve places and turn and shoot BANG magnesium shoots copper dead with a bullet (electron) and wins the lady (Magnesium was the fastest to REACT
What do electrons always go from?
The most reactive metal (oxidation) to the least reactive metal (reduction) and electricity has been made when This happens
What is a battery known as in chemistry?
What is a cell made up of?
Two different metals connected by an electrolyte
What is an electrolyte?
An ionic solution used to complete the circuit
What happens the further apart the metals are in the electrochemical series?
The higher the voltage produced
How can electricity be produced in a cell?
By connecting two different metals in a solution for their own ions
What is the purpose of the ion bridge?
To complete the circuit
What the ion bridge?
A piece of filter paper soaked in salt water or some other ionic solution
What is another type of cell?
One which only one metal is involved and the other half of the cell contains SO3 2- ions or l2 with a carbon electrode, in these cells the electrons flow from the non metal to the metal
What is a fuel cell?
A device that converts chemical energy from a fuel such as hydrogen into electrical energy through a chemical reaction with oxygen or some other oxidising agent.
What is the difference between Batteries and fuel cells?
Fuel cells require an outside source of fuel, while batteries contain the chemicals that they require to produce electricity
What batteries are non rechargeable?
Batteries such as the zinc-carbon battery, when the chemicals are used up it should be recycled
What happens when the direction of electrical flow in a rechargeable battery reverses?
The chemical reaction that occurred in the battery in the first place reverses making it ready for use again
What is an example of a rechargeable battery?
The lead-acid battery which is found in cars
Cell story (part 2)
After the shoot out magnesium marries the lady and they live together happily ever after
The most reactive metal will ALWAYS win the lady (group ion such as sulphate or nitrate)
This explains the concept of Displacement reactions
What happens in Displacement reactions?
The reactive Mayland displaces a metal that is less reactive from solution
Example of a Displacement reaction
Mg(S) +CUSO4(aq) =MgSO4+Cu(s)
The most reactive metal always joins to the group ion)(the non metal So4 in this case)
What will happen if the group ion is already combined to the most reactive metal?
No reaction will occur
Example - Pb+ZnSO4=no reaction
What happens to hydrogen when a metal reacts with acid?
Hydrogen is released
What is it known as when substances lost electrons?
What is it known as when substances gain electrons?
Oxidation Is Loss
Reduction Is Gain
What is happening when a metal element is reacting to form a compound?
It's being oxidised
A reduction reaction is the opposite of oxidation it is...
The gaining of electrons
What is a redox reaction?
A reaction where both oxidation and reduction take place.
Why are all Displacement reactions redox reactions?
One metal is gaining electrons (reduction) and one metal is losing electrons (oxidation)
What do we know about metals that have been found in nature?
They have been there for a long time and have probably reacted with the oxygen In the air and water
Are most metals discovered as a pure metal?
No they are mostly discovered as compound which are called ores in this state
What metals are found as pure metals and why?
The less reactive metals like gold and Platinum because they are very unreactive
What metals are hardest to remove from their ores?
The more reactive the metal, the more difficult to remove from their ores
How are less reactive metals removed from their ores?
By heating, some need to be heated with a reducing agent such as carbon monoxide or carbon to remove the oxygen
What is a reducing agent?
A substance that can donate electrons
How are more reactive metals removed from their ores?
By using electrolysis to remove impurities,