Common Misconceptions
Part of Purity & Formulations — GCSE Chemistry
This common misconceptions covers Common Misconceptions within Purity & Formulations for GCSE Chemistry. Revise Purity & Formulations in Chemical Analysis for GCSE Chemistry with 20 exam-style questions and 12 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 9 of 13 in this topic. Use this common misconceptions to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 9 of 13
Practice
20 questions
Recall
12 flashcards
⚠️ 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.