Potassium perchlorate (KClO4) has a lattice energy of -599 kJ/mol and a heat of hydration of -548 kJ/mol. Find the heat of solution for potassium perchlorate and determine the temperature change that occurs when 10.0 g of potassium perchlorate is dissolved with enough water to make 100.0 mL of solution. (Assume a heat capacity of 4.05 J/g°C for the solution and a density of 1.05 g/mL.)

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Identify the given values: lattice energy of KClO4 is -599 kJ/mol, heat of hydration is -548 kJ/mol.

Calculate the heat of solution using the formula: \( \Delta H_{solution} = \Delta H_{lattice} + \Delta H_{hydration} \).

Convert the mass of KClO4 (10.0 g) to moles using its molar mass.

Calculate the total heat change (q) using the formula: \( q = n \times \Delta H_{solution} \), where n is the number of moles.

Determine the temperature change (\( \Delta T \)) using the formula: \( q = m \times C \times \Delta T \), where m is the mass of the solution and C is the heat capacity.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Lattice Energy

Lattice energy is the amount of energy released when gaseous ions combine to form an ionic solid. It is a measure of the strength of the forces between the ions in an ionic compound. A more negative lattice energy indicates a more stable ionic compound, as it requires more energy to break the ionic bonds. In this question, the lattice energy of potassium perchlorate is given as -599 kJ/mol, which is crucial for calculating the heat of solution.

Heat of Hydration

The heat of hydration is the energy change that occurs when ions are surrounded by water molecules and solvated. It is typically exothermic, meaning it releases energy, and is important for understanding how ionic compounds dissolve in water. For potassium perchlorate, the heat of hydration is -548 kJ/mol, which will be used alongside the lattice energy to find the overall heat of solution.

Heat of Solution

The heat of solution is the overall energy change when a solute dissolves in a solvent. It can be calculated using the formula: Heat of Solution = Heat of Hydration + Lattice Energy. This value indicates whether the dissolution process is endothermic or exothermic. In this case, the heat of solution for potassium perchlorate will help determine the temperature change when it is dissolved in water.

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