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2.1 Purity and separating mixtures

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Question 11

A food scientist checks a sample of solid food additive P.

Melting informationTemperature (∘C^\circ\mathrm{C}∘C)
Data book melting point of pure P152
Sample starts to melt145
Sample is completely melted151

Which conclusion is supported by these results?

[1]
A

The sample is impure because it melts over a range of temperatures below 152 ∘C152\,^\circ\mathrm{C}152∘C.

B

The sample is pure because every pure substance melts over a range of temperatures.

C

The sample is pure because it is completely melted at 151 ∘C151\,^\circ\mathrm{C}151∘C, close to the data book value.

D

The sample is impure because impurities raise the temperature at which a solid starts to melt.

Markscheme

2.1 Purity and separating mixtures Questions

  1. GCSE
  2. /Chemistry
  3. /2.1 Purity and separating mixtures

102 exam-style questions on OCR GCSE Chemistry 2.1 Purity and separating mixtures, covering 2.1.1 Pure substances and melting point data, 2.1.2 Relative formula mass and empirical formula, 2.1.3 Formulations as useful mixtures, 2.1.4 Techniques for separating mixtures, and 2.1.5 Chromatography and Rf values. Each one has a worked solution and a mark scheme showing where the marks go.

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