An analytical chemist in an industrial laboratory is analyzing an unlabelled solvent waste container containing a liquid mixture.
State a physical test the chemist can perform to find out if the liquid is a single pure substance or a mixture.
The chemist determines that the sample is a mixture containing hexane, C6H14\text{C}_6\text{H}_{14}C6H14, and cyclohexane, C6H12\text{C}_6\text{H}_{12}C6H12.
What is the empirical formula of hexane?
The boiling point of hexane is lower than the boiling point of cyclohexane.
Describe a method the chemist could use to obtain a sample of pure hexane from the mixture of cyclohexane and hexane.
The chemist obtains 15.8 g15.8\text{ g}15.8 g of hexane from 24.3 g24.3\text{ g}24.3 g of the solvent mixture.
Calculate the percentage by mass of hexane obtained. Give your answer to 2 significant figures.
Hexane reacts with oxygen in a complete combustion reaction. Complete the balanced symbol equation for this reaction:
2C6H14+‾O2→‾CO2+‾H2O2\text{C}_6\text{H}_{14} + \underline{\quad\quad}\text{O}_2 \rightarrow \underline{\quad\quad}\text{CO}_2 + \underline{\quad\quad}\text{H}_2\text{O}2C6H14+O2→CO2+H2O
Practise OCR GCSE Chemistry Purity and separating mixtures with exam-style questions for Foundation and Higher tier. 81 questions, matched to the OCR GCSE Chemistry (J248) specification and written in Paper 1 and Paper 2 (Foundation Tier) or Paper 3 and Paper 4 (Higher Tier) style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.