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Calorimeter
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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
Safety Precautions
- Sodium hydroxide (NaOH) is highly corrosive: it causes severe skin and eye burns. Wear goggles and gloves, and never touch the pellets with bare hands.
- Exothermic dissolution can get dangerously hot: NaOH and CaCl₂ release a lot of heat — add the solid to water in small amounts with stirring, and use enough water so the solution cannot boil or spit.
- Always add acid/solid to water, never water to them: if concentrated H₂SO₄ is used, add it slowly to water; the reverse can boil violently and throw acid.
- Endothermic salts get cold: NH₄Cl and KNO₃ cool the solution — the beaker may feel cold enough to condense moisture, but there is no burn risk.
- Handle the thermometer with care: do not stir with it; a broken thermometer (especially mercury) is a serious hazard. Dispose of all solutions as directed.
Predict Before You Dissolve
Select a solute above, then predict what its dissolution will do. The Add & Dissolve button unlocks once you lock a prediction; choosing a different solute re-arms the gate.
📚 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
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