Chemistry In Society #1: Metals Flashcards
What does each atom in a metal do?
Loses its outer electrons to form positive ions
What do these positive metal ions do?
They form a regular, 3 dimensional lattice of positively charged ions
The outer electrons of metal ions can be described as… why?
Delocalised
They are not attached to a particular atom and are free to move around
What does the electrostatic attraction do positive metal ions for the delocalised electrons do?
They BIND the positive ions together
What is electric current?
A flow of charged particles (ions, electrons)
Why can metals conduct electricity?
Because electrons can flow through them without chemical changes taking place
Why is electrolysis the opposite case of metals conducting electricity?
Electrons cannot flow through without chemical changes taking place
What is the reactivity series?
A list of metals in order of reactivity, eg with oxygen, water, and dilute acids
What metals do not react?
Gold, silver
What metals will combine with oxygen when heated?
All ABOVE silver
What is the equation for metals combining with oxygen when heated?
Metal + oxygen -> metal oxide
The higher the metal is in the series,
The more violent the reaction
Metals high in the table are good at…
Losing electrons, therefore are more reactive
What metals react with water?
All above ALUMINIUM
What is the equation for metal reacting with water?
Metal + water -> metal hydroxide + hydrogen
What metals react with a DILUTE ACID?
All above copper
What is the word equation for metals reacting with a dilute acid?
Metal + acid -> salt + hydrogen
Oxidation reaction
One in which electrons are lost or oxygen is gained
Reduction reaction
One in which electrons are gained
What are redox reactions
Ones which involve both reduction and oxidation taking place at the same time
What do you do if the ion-electron equations do not contain equal numbers of electrons?
Balance them. Multiply one or both of the ion-electron equations
What is a displacement reaction?
It involves the formation of a metal from a solution containing its ions by reaction with a metal higher in the ECS
How do you know where to place hydrogen in the ECS?
According to its reaction with dilute hydrochloric acid
Metals can displace hydrogen ions to
Produce hydrogen gas
Where is hydrogen in the ECS?
between lead and copper
What are ores?
Naturally occurring compounds of metals
Most ores are oxides
Why were gold, silver, and copper the first metals to be discovered?
They are found uncombined in the earth’s crust
The extraction of gold, silver, copper metal ores …
Does NOT involve a chemical reaction
What do we have to do to more reactive metals unlike CU AG AU?
extract them from their ores
The method of extraction depends on…
The reactivity of the metal
The more reactive the metal,
The stronger the bonds which hold the compound together, the more energy required to extract it
What type of reaction is the extraction of any metal from its ore?
A reduction one
How can we extract metals below copper?
Using heat alone
Equation for extraction using heat alone
Metal oxide -> metal + oxygen
How can we extract oxides of metals above MERCURY and below aluminium in the reactivity series?
Heating with carbon or carbon monoxidw
Equation for extraction with heat and carbon / carbon monoxide
Metal oxide + carbon -> metal + carbon dioxide
Metal oxide + carbon monoxide -> metal + carbon dioxide
How do extraction reactions with carbon (monoxide) work?
Because the carbon bonds stronger with the oxygen than the metal dows
Carbon and carbon monoxide are
Reducing agents
Why does heating with carbon not work as an extraction method for oxides of metals above zinc?
The metal bonds more strongly with the oxygen than carbon does
How are oxides of metals above zinc extracted?
Electrolysis of molten compounds using a direct current
What is electrolysis?
The decomposition of an ionic compound into its elements
Why must a direct current (DC) suple be used in electrolysis?
If the products are ti be identified
Why does electrolysis work?
When the compound becomes molten, the ionic lattice breaks and the ions are free to move
Where are the positive metal ions attracted to in electrolysis? What do they do there?
The negative electrode
They gain electrons and form metals ions
Ions flow through…
Solutions
Electrons flow through…
Metal wires
Electrochemical cells: (3)
- convert chemical cells into electric energy
- contain one substance which gives up electrons
- contain another substance which accepts electrons
What is an electrolyte?
A substance which completes the circuit by allowing ions to move through it
What does a cell consist of?
- 2 different metals
- an electrolyte to complete the circuit
Why does NaCl solution work as an electrolyte?
It is an ionic solution, so ions can move through it
The voltage between different pairs of metals…
Varies
Metals can be sorted by their voltages. How?
In the ECS
In conclusion, the ECS is
A list of metals (&hydrogen) in order of their ability to lose electrons and form ions in solution
What does the ECS also contain?
Reactions for non-metals
How can non-metals be used in half cells with a graphite rod?
To make electrical contact with the solution
Direction of electron flow (3)
- ion higher in the ECS gives away electrons (oxidation)
- ion lower in ECS gains those electrons (redox)
This redox reaction produces an electric current
What is a half cell?
A metal in contact with solution of its ions
What is the only way half cells can produce electricity?
When 2 are joined together
How do ions move between the two half cells? Why?
Using the ion bridge.
It completes the circuit.
How do electrons flow from the metal higher in the ECS to the metal lower in the ECS?
Through the wires and meter
