2.4 Reactivity Series Flashcards
How much does potassium react with water?
Reacts violently
How much does sodium react with water?
Reacts quickly
How much does calcium react with water?
Reacts less strongly
Calcium + Water word equation?
calcium + water ⟶ calcium hydroxide + hydrogen
Calcium + Water chemical equation?
Ca(s) + 2H₂O(l) ⟶ Ca(OH)₂(aq) + H₂(g)
Which metals react with dilute acids?
Metals above hydrogen in the reactivity series.
General equation for metal + acid?
metal + acid ⟶ salt + hydrogen
Magnesium + sulfuric acid chemical equation?
Mg + H₂SO₄ ⟶ MgSO₄ + H₂
Magnesium + Hydrochloric Acid chemical equation?
Mg + 2HCl ⟶ MgCl₂ + H₂
What happens during a metal displacement reaction?
A more reactive metal will displace a less reactive metal from its compounds
Simple reactivity series? (With Mnemonic)
Potassium - Please
Sodium - Send
Lithium - Lions
Calcium - Cats
Magnesium - Monkeys
Aluminium - And
Carbon - Cute
Zinc - Zebras
Iron - Into
Hydrogen - Hot
Copper - Countries
Silver - Signed
Gold - Gordon
2 examples of displacement reactions?
- Reacting a metal with a metal oxide (by heating)
- Reacting a metal with an aqueous solution of a metal compound
What is rusting?
- Rusting is a chemical reaction between iron, water and oxygen to form hydrated iron(III)oxide
- Rusting is a redox process and it occurs faster in salty water since the presence of sodium chloride speeds up the reaction
Rusting of Iron word equation?
Iron + Water + Oxygen → Hydrated Iron(III) Oxide
Rusting of iron chemical equation?
4Fe(s) + 3O₂(g) + xH₂O(l) → 2Fe₂O₃.xH₂O(s)
Methods for preventing iron rusting?
- Barrier Methods
- Galvanising
- Sacrificial corrosion
How is rusting prevented using barrier methods?
- Rust can be prevented by coating iron with barriers that prevent the iron from coming into contact with water and oxygen
- Examples of barriers are oil and plastic
- However, if the coatings are washed away or scratched, the iron is once again exposed to water and oxygen and will rust
How is rusting prevented using galvanising?
- Iron can be prevented from rusting making use of metals higher in reactivity than iron
- Galvanising is a process where the iron to be protected is coated with a layer of zinc
- ZnCO₃ is formed when zinc reacts with oxygen and carbon dioxide in the air and protects the iron by the barrier method.
- If the coating is damaged or scratched, the iron is still protected from rusting because zinc preferentially corrodes as it is higher up the reactivity series than iron.
How is rusting prevented using sacrificial corrosion?
- Sacrificial corrosion occurs when a more reactive metal is intentionally allowed to corrode.
- An example of this occurs with ships’ hulls which sometimes have large blocks of magnesium or magnesium alloys attached
- The blocks slowly corrode and provide protection to the hull in the same way the zinc does by pushing electrons onto the iron which prevents it from being oxidised to iron(III) ions
What is oxidation?
Oxidation is any reaction in which a substance gains oxygen.
What is reduction?
Reduction is a reaction in which a substance loses oxygen.
What are redox reactions?
Where oxidation cannot occur without reduction happening simultaneously.
What is the oxidising agent?
What supplies the oxygen. It accepts electrons.
What is the reducing agent?
A reducing agent is a substance that donates electrons in a redox reaction.
What is oxidation in terms of electrons?
Oxidation is the loss of electrons (OIL)
What is reduction in terms of electrons?
Reduction is the gain of electrons (RIG)
Observations from reactions between magnesium, iron, zinc with dilute sulfuric acid.
- Magnesium: Rapid bubbling, gas given off (hydrogen), metal dissolves.
- Zinc: Metal dissolves forming a colourless solution, gas given off slowly.
- Iron: Slow reaction, small bubbles seen.
Define the term salt?
A salt is the ionic compound produced when a metal reacts with an acid.
What is a spectator ion?
A spectator ion is an ion that does not participate in the chemical reaction and appears unchanged on both sides of the equation.
Define the term corrosion?
The term corrosion means the degradation of a metal surface through a chemical reaction.
Why is rusting bad?
Rusting weakens the structure and integrity of iron over time as more iron is lost.
