This comparison covers Pure vs Impure: Everyday Examples within Purity & Formulations for GCSE Chemistry. Revise Purity & Formulations in Chemical Analysis for GCSE Chemistry with 22 exam-style questions and 12 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 8 of 13 in this topic. Use this comparison to connect the idea to the wider topic before moving on to questions and flashcards.
⚖️ Pure vs Impure: Everyday Examples
| Item | Pure or Impure? | Explanation |
|---|---|---|
| Distilled water | Pure | Only H₂O molecules |
| 24-carat gold | Nearly pure | Very high % gold; minimal other metals |
| Tap water | Impure | Contains dissolved salts, chlorine, fluoride |
| Sea water | Impure | Water plus ~3.5% dissolved salts |
| Air | Impure | Mixture of gases: 78% N₂, 21% O₂, 1% others |
| Orange juice | Impure | Water, sugars, acids, vitamins — many compounds |
| Steel | Impure (formulation) | Iron mixed with carbon and other elements |
Practice questions for Purity & Formulations
In chemistry, what does it mean for a substance to be described as 'pure'?
Explain why the presence of impurities in a substance lowers its melting point and causes it to melt over a range of temperatures.
Quick recall flashcards
Give 3 examples of formulations
1) Paint (pigment + binder + solvent), 2) Medicine tablets (active ingredient + binder + filler), 3) Petrol (hydrocarbons + octane improvers + additives)
What is a formulation?
A mixture designed to have specific properties for a particular purpose, with each component in measured quantities