Cristalización Exotérmica de Acetato de Sodio

Medición del calor liberado durante la cristalización instantánea

Thermochemistry Intermediate (High School) 30 min ~$8,00

Objetivo

Cuantificar el calor liberado durante la cristalización de acetato de sodio supersaturado usando calorimetría.

Antecedentes

When supersaturated sodium acetate crystallizes, it releases stored energy as heat. By triggering crystallization inside a calorimeter and measuring the temperature rise, the enthalpy of crystallization can be determined. This is the same principle used in reusable hand warmers.

Advertencias de seguridad

  • Hot solution during preparation
  • Crystallization releases heat — container gets warm

EPP requerido

goggles

Materiales

  • Sodium acetate trihydrate (80 g)
  • Distilled water (150 mL)

Equipamiento

Polystyrene cup calorimeter Hot plate Thermometer Beaker (250 mL) Stirring rod

Procedimiento

1

Dissolve 80 g sodium acetate trihydrate in 20 mL water by heating to about 70°C. Stir until clear.

8 min Handle hot solution carefully
2

Pour the solution into the polystyrene cup calorimeter. Allow to cool undisturbed to room temperature.

15 min
3

Record the temperature of the supersaturated solution.

1 min
4

Add a single small crystal of sodium acetate to trigger crystallization. Immediately stir gently and record temperature every 15 seconds.

3 min
5

Record the maximum temperature reached.

1 min
6

Calculate the heat released: q = mcΔT. Determine ΔH of crystallization per mole.

5 min

Resultados esperados

Temperature should rise 15-25°C above room temperature. The enthalpy of crystallization is approximately -19.7 kJ/mol for sodium acetate trihydrate. Measured values should be within 20% of this.

Limpieza

The sodium acetate can be remelted and reused. Rinse the calorimeter. Non-toxic — can go down the drain.

Detalles

Categoría
Thermochemistry
Dificultad
Intermediate (High School)
Duración
30 min
Costo estimado
$8,00
Pasos
6
Materiales
2

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Frequently Asked Questions

What is the objective of Cristalización Exotérmica de Acetato de Sodio?
Cuantificar el calor liberado durante la cristalización de acetato de sodio supersaturado usando calorimetría.
How difficult is Cristalización Exotérmica de Acetato de Sodio?
This experiment is rated as Intermediate (High School). It takes approximately 30 minutes to complete.
What safety precautions are needed for Cristalización Exotérmica de Acetato de Sodio?
Key safety precautions include: Hot solution during preparation; Crystallization releases heat — container gets warm.
What materials are needed for Cristalización Exotérmica de Acetato de Sodio?
The main materials required are: Sodium acetate trihydrate, Distilled water.
What results should I expect from Cristalización Exotérmica de Acetato de Sodio?
Temperature should rise 15-25°C above room temperature. The enthalpy of crystallization is approximately -19.7 kJ/mol for sodium acetate trihydrate. Measured values should be within 20% of this.