Common Misconceptions

⚠️ Common Misconceptions

Misconception 1: "Pure means the same as it does in everyday language"

"Pure orange juice" is a marketing term. In chemistry, it is a complex mixture of dozens of compounds. The word "pure" in GCSE chemistry has a strict scientific meaning: one type of element or compound only. Never confuse everyday usage with the chemical definition.

Misconception 2: "Impurities always raise the melting point"

Wrong — impurities lower the melting point (and raise the boiling point). Think of gritting icy roads: salt lowers the freezing point of water, so ice melts at sub-zero temperatures.

Misconception 3: "A pure substance melts quickly at its melting point, then the temperature rises"

During melting, the temperature stays constant until all the solid has melted. The energy input is being used to break intermolecular forces, not to increase temperature. The flat plateau on a heating curve is the key indicator of a pure substance.