Year 9 Chemistry Revision Notes

Flashcards created for revision on key chemistry concepts, including energy changes, reactions of metals, extraction methods, and prevention of rusting.

Exothermic reactions

Reactions that release heat, causing the temperature to increase.

Endothermic reactions

Reactions that absorb heat, causing the temperature to decrease.

Reactivity series of metals

A list that ranks metals based on their reactivity from most reactive to least reactive.

Potassium and water reaction

Potassium reacts violently with water, floating and fizzing, and burns with a lilac flame.

Sodium and water reaction

Sodium melts into a ball, floats, and fizzes on the water surface.

Lithium and water reaction

Lithium moves slowly on the water surface while fizzing.

Equation for lithium and water

$$2Li + 2H_2O ightarrow 2LiOH + H_2$$

Calcium with water

Calcium fizzes a lot with water and generates heat.

Magnesium with water

Magnesium produces a few bubbles on the surface when reacting with water.

Zinc, iron, and copper with water

Zinc, iron, and copper do not react with water.

Reaction of metals with acid

More reactive than water, so metals lower in the reactivity series will react, producing gas.

Zinc and hydrochloric acid equation

$$Zn + 2HCl ightarrow ZnCl_2 + H_2$$

MASH reaction

Metal + Acid → Salt + Hydrogen.

Displacement reactions

A more reactive metal displaces a less reactive metal in a compound.

Extraction of metals

Metals low in the reactivity series are extracted from their oxides by heating with carbon.

Bioleaching

A method of extracting metals using bacteria to produce a leachate solution.

Phytomining

A method of using plants to concentrate metals by taking them up through their roots.

Rusting of iron

Requires both oxygen from air and water; prevented by barriers like painting or galvanizing.

Sacrificial protection

A method that uses a more reactive metal to protect a less reactive metal from corrosion.