Hydrate Calculations and Problem-Solving Techniques
This page presents two detailed examples of hydrate-related problems with step-by-step solutions, demonstrating key concepts in hydrate chemistry and stoichiometry.
The first problem involves calculating the mass percentage of water released when dissolving calcium chloride hexahydrate (CaCl₂·6H₂O) in water. The solution process illustrates how to determine the amount of water in the hydrate crystal and calculate its percentage in the final solution.
Vocabulary: Hydrate - A compound that contains water molecules as part of its crystal structure.
Example: For CaCl₂·6H₂O, the calculation shows that 10.85g of water is released from the hydrate crystal when 22g of the hydrate is dissolved.
Highlight: The mass percentage of water from the hydrate in the final solution is calculated to be 9.1%.
The second problem focuses on determining the mass of barium chloride dihydrate (BaCl₂·2H₂O) needed to prepare a specific volume and concentration of barium chloride solution. This example demonstrates the application of molar mass, concentration, and stoichiometric calculations.
Definition: Molar concentration (molarity) - The number of moles of solute per liter of solution.
Example: To prepare 250 cm³ of a 0.5 molar BaCl₂ solution, 30.5g of BaCl₂·2H₂O is required.
These problems showcase important techniques for solving hydrate-related questions, including:
- Calculating the mass of water in hydrates
- Determining mass percentages in solutions
- Converting between hydrate and anhydrous salt masses
- Using molar concentrations in solution preparation
The detailed solutions provide a valuable resource for students studying hydrate properties, dissolution processes, and stoichiometric calculations involving hydrates.
