Topic 4- Extracting Metals And Equilibra Flashcards
What is oxidation?
The Loss of electrons
Or the gain of oxygen
What is reduction ?
The gain of electrons
The loss of oxygen
What’s a good way to remember the difference between oxidation and reduction?
OIL RIG
oxidation is loss (of electrons)
Reduction is gain (of electrons)
Oxidation Is Loss Reduction Is Gain
What’s an example of oxidation?
E.g. when metals react with oxygen, metal oxides are produced:
Magnesium + oxygen → magnesium oxide
2Mg + O2 → 2MgO
What’s an example of reduction ?
E.g. when metal oxides lose oxygen and return to their atomic form:
Iron oxide + carbon monoxide → iron + carbon dioxide
Fe2O3 + 3CO → 2Fe + 3CO2
Sodium + oxygen —> ?
Sodium oxide
Mg(s) + 2H+(aq) + 2Cl-(aq) → Mg2+(aq) + 2Cl-(aq) + H2(g)
In this ionic equation, what’s being oxidised and what’s being reduced?
Mg2+ is being oxidised
H+ is being reduced
Mg(s) + 2H+(aq) + 2Cl-(aq) → Mg2+(aq) + 2Cl-(aq) + H2(g)
In this ionic equation, what is are the spectator ions ?
2Cl-(aq) ions
When reacting with other substances, what ions do metal atoms always become ?
metal atoms always form positive ions.
What is the reactivity of a metal linked to ?
how easy it is for a metal to form its positive ion
What order can metals be arranged in ?
in order of their reactivity.
What are examples of highly unreactive metals ?
Gold and platinum
Where are gold and platinum found ?
And what do we call them ?
These metals are found in the Earth’s crust as pure metals. We call them native metals.
Which non-metals are often included in the reactivity series of metals for reference?
Carbon
Hydrogen
What is a displacement reaction ?
A more reactive metal (one that forms positive ions more easily) can remove a less reactive metal from a compound.
When can a metal displace another metal from a compound ?
A metal can only displace another metal from a compound if it is located above it in the reactivity series.
What’s an example of a displacement reaction ?
Calcium + copper sulfate → calcium sulfate + copper
Calcium is higher in the reactivity series than copper. This means that calcium is able to displace copper from a copper sulfate solution to create calcium sulfate.
Calcium + copper sulfate → calcium sulfate + copper
Ca(s) + CuSO4(aq) → CaSO4(aq) + Cu(s)
Platinum, on the other hand, is less reactive than copper and so would not be able to displace copper from a copper sulfate solution.
What are redox reactions ?
Displacement reactions are examples of redox reactions.
In metal displacement reactions, the more reactive metal loses electrons (oxidised) and the less reactive metal gains electrons (reduced).
What are the products of the reaction between magnesium and copper sulfate ?
Magnesium sulfate and copper
What is the word and symbol equation for the displacement reaction :
Sodium bromide + chlorine → ? + ?
2NaBr + Cl2 → ? + ?
Sodium bromide + chlorine → sodium chloride + bromine.
2NaBr + Cl2 → 2NaCl + Br2
What is the half equation for bromine ions in displacement reactions ?
Bromide ions are oxidised (electrons are lost):
2Br- → Br2 +2e-.
What is the half equation for chlorine ions in displacement reactions ?
Chlorine is reduced (electrons are gained):
Cl2 + 2e- → 2Cl-.
What are the spectator ions in the displacement reaction-
Sodium bromide + chlorine → sodium chloride + bromine.
2NaBr + Cl2 → 2NaCl + Br2
Sodium ions
What are spectator ions ?
A spectator ion is an ion that doesn’t change during a chemical reaction.
What is the reactivity series order ?
Order From most reactive to least
Potassium Sodium Lithium Calcium Magnesium Aluminium CARBON - not a metal Zinc Iron HYDROGEN - not a metal Copper Silver Gold Platinum
2NaBr(aq) + Cl2(g) → 2NaCl(aq) + Br2(l)
Which is the spectator ion in this equation?
Na +
When Potassium, sodium and lithium all react quickly with cold water to produce what ?
a metal hydroxide and hydrogen gas
What happens to potassium when reacted with cold water ?
Potassium is the most reactive so reacts very quickly.
The hydrogen produced ignites instantly and the metal also sets alight, sparking and burning with a lilac flame
What colour is the flame of potassium when it reacts with water ?
lilac flame
What happens to sodium when reacted with cold water ?
Sodium fizzes rapidly and melts to form a ball that moves around on the water surface.
What happens to lithium when reacted with cold water ?
Lithium fizzes steadily and floats, becoming smaller until it eventually disappears
Most metals react with dilute acids to give what ?
a salt (e.g. copper chloride) and hydrogen gas
What metals don’t react with dilute acids ?
copper, silver, gold and platinum.
What metals react with dilute acids but not cold water ?
magnesium, aluminium, zinc, iron and lead (iron and lead react slowly).
Metals don’t have to be that reactive to react with dilute acids.
Why is carbon used to extract metals?
Reducing a metal with carbon will result in the extraction of the metal if the metal is lower in the reactivity series than carbon.
Carbon is used because it is cheap and abundant.
How is carbon used to extract metals?
In the reduction, the metal oxide loses oxygen to form a pure metal.
Reduction with carbon normally involves heating the metal oxide in the presence of the carbon, which is often used in the form of coal.
What form is carbon often used in when reducing metal oxides?
Coal
metal+acid→?+?
metal+acid→salt+hydrogen
Fact about reactivity series’s
Potassium down to aluminium are more reactive than carbon and so cannot be extracted by reduction with carbon.
Silver, gold and platinum are either found as natural elements or can be simply extracted by heating directly in air.
The remaining metals - zinc, iron, and copper - are all commonly extracted by reduction with carbon.
What type of reaction is used when extracting metals using carbon ?
Reduction
