A manufacturer checks a batch labelled as solid W.
The accepted melting point of solid W is 134 ∘C134\ ^\circ\text{C}134 ∘C. A sample from the batch melted sharply at 129 ∘C129\ ^\circ\text{C}129 ∘C.
A chemist concludes that the batch is pure solid W.
Which comment correctly evaluates the chemist's conclusion?
The chemist's conclusion is not supported because the measured melting point does not match the accepted melting point of solid W.
The chemist's conclusion is supported because melting sharply at one temperature is sufficient evidence for pure solid W.
The chemist's conclusion is supported because pure solid W should melt below its accepted melting point.
The chemist's conclusion is not supported because pure solid W should melt over a range ending at its accepted melting point.
113 exam-style questions on AQA GCSE Chemistry 8.1 Purity, formulations and chromatography, covering 8.1.1 Pure substances, 8.1.2 Formulations, and 8.1.3 Chromatography. Each one has a worked solution and a mark scheme showing where the marks go.