Ethanol (C₂H₅OH) is used as a solvent in an organic synthesis
CHEMISTRY · Multi-part · CBSE · Chemistry · Some Basic Concepts of Chemistry · Some Basic Concepts of Chemistry
Problem
Ethanol (C₂H₅OH) is used as a solvent in an organic synthesis. A chemist measures out 8.46 g of ethanol and transfers it to a volumetric flask, then adds enough water to obtain a final solution volume of 125 mL. Density data for pure ethanol (0.789 g mL⁻¹ at 25 °C) are provided on the reagent bottle but are not directly required for the calculation.
Atomic masses (g mol⁻¹): C 12.01, H 1.01, O 16.00
(1) Calculate the number of moles of ethanol that were placed in the flask.
(2) Determine the molarity of ethanol in the prepared solution, expressing your answer with the correct number of significant figures.
(3) Suppose the chemist had mistakenly used the density value of ethanol to convert 8.46 g to a volume before proceeding. Explain why that extra step would not alter the final molarity calculation.