Kimia Kompres Dingin

Mempelajari pelarutan endotermik amonium nitrat

Thermochemistry Beginner (Middle School) 20 menit ~$6,00

Tujuan

Ukur perubahan suhu saat amonium nitrat larut dalam air, mendemonstrasikan proses pelarutan endotermik yang digunakan dalam kompres dingin instan.

Latar Belakang

Ammonium nitrate dissolves endothermically in water, absorbing heat from the surroundings and causing a significant temperature drop. This principle is used in commercial instant cold packs for first aid. The dissolution has ΔH = +25.7 kJ/mol.

Peringatan Keselamatan

  • Ammonium nitrate is an oxidizer — keep away from organic materials and heat
  • Do not mix with anything other than water for this experiment
  • Wear goggles

APD yang Diperlukan

goggles

Bahan

  • Ammonium nitrate (NH₄NO₃) (30 g)
    Or from a commercial cold pack
  • Distilled water (100 mL)
    Room temperature

Peralatan

Polystyrene cup calorimeter Thermometer Stirring rod Analytical balance

Prosedur

1

Add 100 mL of distilled water to the polystyrene cup calorimeter. Record the initial temperature.

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2

Weigh 30 g of ammonium nitrate.

2 menit Ammonium nitrate is an oxidizer
3

Add the ammonium nitrate to the water. Stir gently to dissolve.

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4

Record the temperature every 30 seconds as it drops. Note the minimum temperature.

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5

Feel the outside of the cup — it should feel cold.

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6

Calculate ΔH of dissolution per mole: q = mcΔT, n = mass/M(NH₄NO₃), ΔH = q/n.

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Hasil yang Diharapkan

Temperature should drop 15-20°C. 30 g NH₄NO₃ = 0.375 mol. q = 100 × 4.18 × ΔT. Calculated ΔH should be approximately +25 kJ/mol (±15%).

Pembersihan

The ammonium nitrate solution is safe to dispose down the drain (dilute). Rinse the calorimeter.

Detail

Kategori
Thermochemistry
Tingkat Kesulitan
Beginner (Middle School)
Durasi
20 menit
Perkiraan Biaya
$6,00
Langkah
6
Bahan
2

Eksperimen Lainnya

Demonstrasi Reaksi Endotermik 20 min Entalpi Fusi Es 25 min Kalorimetri Cangkir Kopi 40 min Kapasitas Panas Spesifik Logam 40 min Kristalisasi Eksotermik Natrium Asetat 30 min Panas Pembakaran Magnesium 50 min Pelarutan Tidak Selalu Eksotermik 25 min Simulasi Kalorimetri Bom 45 min Verifikasi Hukum Hess 60 min

Frequently Asked Questions

What is the objective of Kimia Kompres Dingin?
Ukur perubahan suhu saat amonium nitrat larut dalam air, mendemonstrasikan proses pelarutan endotermik yang digunakan dalam kompres dingin instan.
How difficult is Kimia Kompres Dingin?
This experiment is rated as Beginner (Middle School). It takes approximately 20 minutes to complete.
What safety precautions are needed for Kimia Kompres Dingin?
Key safety precautions include: Ammonium nitrate is an oxidizer — keep away from organic materials and heat; Do not mix with anything other than water for this experiment; Wear goggles.
What materials are needed for Kimia Kompres Dingin?
The main materials required are: Ammonium nitrate (NH₄NO₃), Distilled water.
What results should I expect from Kimia Kompres Dingin?
Temperature should drop 15-20°C. 30 g NH₄NO₃ = 0.375 mol. q = 100 × 4.18 × ΔT. Calculated ΔH should be approximately +25 kJ/mol (±15%).