📖 Theory & Concepts ▼

Enthalpy of Dissolution

The heat change when 1 mole of a substance dissolves in a solvent to form an infinitely dilute solution.

Endothermic (ΔH > 0)

Heat absorbed → Solution cools down

Examples: NH₄Cl, KNO₃, NH₄NO₃

Exothermic (ΔH < 0)

Heat released → Solution heats up

Examples: NaOH, CaCl₂, H₂SO₄

Energy Components

  • Lattice Energy: Energy to break crystal lattice (always +ve, endothermic)
  • Hydration Energy: Energy released when ions are solvated (always -ve)
Net Effect:

ΔH_dissolution = ΔH_lattice + ΔH_hydration

If |hydration| > |lattice| → Exothermic

Select Solute

Calorimeter

50°40°30°20°10°
25.0°C
100 mL Water

📊 Data

Initial Temperature
25.0°C
Final Temperature
--
ΔT (Change)
--
Process Type
--
ΔH Calculation:
q = m × c × ΔT
m = 100g, c = 4.18 J/g°C

📚 Theory

Endothermic Dissolution
• Absorbs heat from surroundings
• Temperature decreases
• ΔH > 0 (positive)
Examples: NH₄Cl, KNO₃, NH₄NO₃
Exothermic Dissolution
• Releases heat to surroundings
• Temperature increases
• ΔH < 0 (negative)
Examples: NaOH, H₂SO₄, CaCl₂

Observations

Select a solute to begin...