Which row in the table correctly describes a pure substance in chemistry?
RowCompositionMelting pointAMixture of compoundsOver a range of temperaturesBSingle element or compoundOver a range of temperaturesCMixture of compoundsAt a specific, sharp temperatureDSingle element or compoundAt a specific, sharp temperature \begin{array}{|c|l|l|}\hline \textbf{Row} & \textbf{Composition} & \textbf{Melting point} \\ \hline \textbf{A} & \text{Mixture of compounds} & \text{Over a range of temperatures} \\ \hline \textbf{B} & \text{Single element or compound} & \text{Over a range of temperatures} \\ \hline \textbf{C} & \text{Mixture of compounds} & \text{At a specific, sharp temperature} \\ \hline \textbf{D} & \text{Single element or compound} & \text{At a specific, sharp temperature} \\ \hline \end{array} RowABCDCompositionMixture of compoundsSingle element or compoundMixture of compoundsSingle element or compoundMelting pointOver a range of temperaturesOver a range of temperaturesAt a specific, sharp temperatureAt a specific, sharp temperatureRow A
Row B
Row C
Row D
46 exam-style questions on OCR GCSE Chemistry Purity and separating mixtures. Each one has a worked solution and a mark scheme showing where the marks go.