Neco 2025 Chemistry Question 4

Practice essay / theory question 4 from the 2025 Neco Chemistry examination. This question covers mole concept, empirical formula, molecular formula, stoichiometry, combustion, percentage yield .

Neco 2025 Chemistry Essay / Theory

Topics: mole concept empirical formula molecular formula stoichiometry combustion percentage yield

Question 4 NECO • 2025 • CHEMISTRY • essay

The structural diagram of an unknown organic compound is shown in the illustration. The diagram depicts a six‑membered ring containing six carbon atoms, each bearing appropriate hydrogen atoms and hydroxyl groups, together with a CH₂OH side group attached to one carbon. No other atoms are present. Using the information from the diagram, answer the following questions.

Question Parts

( a )

Determine the empirical formula of the compound directly from the structural diagram.

( b )

The experimentally determined molar mass of the compound is 180 g·mol⁻¹. Using the empirical formula obtained in part (a), calculate the molecular formula of the compound.

( c )

When the compound undergoes complete combustion in excess oxygen, it yields carbon dioxide and water. (i) Write the balanced chemical equation for the combustion of one mole of the compound. (ii) Calculate the volume (in litres at STP) of CO₂ produced when 2.00 g of the compound is burnt completely.

( d )

In a laboratory synthesis, 0.50 mol of the compound reacts with excess reagent X to give product Y (molar mass of Y = 150 g·mol⁻¹) with an isolated yield of 80 %. (i) Calculate the theoretical mass of product Y that could be obtained. (ii) Calculate the actual mass of product Y obtained after the reaction.

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About This Question

This is Neco 2025 Chemistry Question 4. It is one of the essay questions from the 2025 Neco Chemistry examination.

The question covers mole concept, empirical formula, molecular formula, stoichiometry, combustion, percentage yield .

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