Reactivity Series and Metal Extraction
The reactivity series of metals is a fundamental concept in GCSE Chemistry, ranking metals based on their tendency to form positive ions. This series is crucial for understanding various chemical reactions and extraction processes.
Reactivity Series Order
The reactivity series mnemonic helps students remember the order of metals from most to least reactive:
Highlight: Potassium, Sodium, Lithium, Calcium, Magnesium, Aluminium, Zinc, Iron, Tin, Lead, Copper, Silver, Gold
This order is essential for predicting chemical reactions and understanding metal extraction methods.
Metal Reactions and Displacement
When metals react with oxygen, they form metal oxides. This process is an example of oxidation, where the metal loses electrons.
Example: Metal + Oxygen → Metal Oxide
Displacement reactions occur when a more reactive metal replaces a less reactive metal in a compound:
Definition: Displacement reaction - A chemical reaction where a more reactive element takes the place of a less reactive element in a compound.
Extracting Metals from Ores
The extraction of metals GCSE topic covers how metals are obtained from their ores. The method used depends on the metal's position in the reactivity series:
- Metals below carbon can be extracted using carbon reduction
- Metals above carbon require electrolysis for extraction
Vocabulary: Metal ore - A rock containing enough metal to make extraction economically viable.
Acid-Base Reactions and Salt Formation
Acids react with metals, bases, and carbonates to form salts. These reactions are crucial in understanding oxidation and reduction GCSE chemistry:
- Metal + Acid → Salt + Hydrogen
- Acid + Base → Salt + Water
- (Metal) Carbonate + Acid → Salt + Water + Carbon Dioxide
Example: Practical salt formation involves neutralization, filtration, and crystallization steps.
pH Scale and Indicators
The pH scale measures the acidity or alkalinity of solutions:
- pH < 7: Acidic
- pH = 7: Neutral
- pH > 7: Alkaline
Indicators, such as litmus paper, change color based on the pH of a solution, helping to identify acids and alkalis.
