A solid sample of calcium chloride dihydrate, CaCl₂·2H₂O
CHEMISTRY · Multi-part · CBSE · Chemistry · Some Basic Concepts of Chemistry · Some Basic Concepts of Chemistry
Problem
A solid sample of calcium chloride dihydrate, CaCl₂·2H₂O, is delivered from a reagent bottle to a weighing boat. The balance reading increases from 65.278 g to 70.006 g once the sample has been added. The sample is rinsed into a graduated cylinder that already contains 15.0 mL of distilled water. After the solid completely dissolves, additional water is added until the total volume in the cylinder reaches 200.0 mL.
Atomic masses (g mol⁻¹): Ca 40.08, Cl 35.45, H 1.01, O 16.00
(1) Determine the number of moles of CaCl₂·2H₂O present in the solution.
(2) Calculate the molarity of the resulting calcium chloride solution.
(3) Explain, with reference to significant figures, why reporting the molarity as 0.1894 M would be inappropriate for the data provided.