ऊष्माशोषी अभिक्रिया प्रदर्शन

बेरियम हाइड्रॉक्साइड और अमोनियम थायोसाइनेट की ठंडी अभिक्रिया

Thermochemistry Intermediate (High School) 20 मिनट ~$12.00

उद्देश्य

एक नाटकीय रूप से ऊष्माशोषी अभिक्रिया प्रदर्शित करें जहां मिश्रण इतना ठंडा हो जाता है कि फ्लास्क के बाहर पानी जम जाता है।

पृष्ठभूमि

When barium hydroxide octahydrate reacts with ammonium thiocyanate, the temperature drops to approximately -20°C. This endothermic reaction absorbs so much heat from the surroundings that water on the outside of the flask freezes, effectively gluing the flask to a wet board.

सुरक्षा चेतावनियाँ

  • Barium compounds are toxic if ingested
  • Ammonia gas is released — work in fume hood or ventilated area
  • Wear gloves when handling barium hydroxide
  • Do not inhale the ammonia fumes

आवश्यक PPE

goggles gloves lab_coat

सामग्री

  • Barium hydroxide octahydrate (32 g)
    Toxic
  • Ammonium thiocyanate (16 g)
  • Water (5 mL)
    On the board

उपकरण

250 mL Erlenmeyer flask Wooden board Thermometer Stirring rod

प्रक्रिया

1

Pour a few drops of water onto the wooden board to create a wet spot.

1 मिनट
2

Add 32 g barium hydroxide octahydrate to the flask.

2 मिनट Wear gloves — barium is toxic
3

Add 16 g ammonium thiocyanate to the flask. Stir the mixture with a glass rod.

2 मिनट Ammonia released — ventilation
4

Place the flask on the wet spot on the board. Insert the thermometer.

1 मिनट
5

Observe the temperature dropping dramatically. Record the minimum temperature.

5 मिनट Do not inhale fumes
6

After 5 minutes, try to lift the flask. It should be frozen to the board.

2 मिनट
7

Explain that the reaction absorbed heat from the surroundings, freezing the water beneath.

2 मिनट

अपेक्षित परिणाम

The temperature should drop to approximately -20°C within minutes. The flask should freeze to the wet board. A strong smell of ammonia confirms the reaction is proceeding.

सफाई

Allow to warm to room temperature. Dispose of barium waste in heavy metal waste container. Rinse flask and ventilate area thoroughly.

विवरण

श्रेणी
Thermochemistry
कठिनाई
Intermediate (High School)
अवधि
20 मिनट
अनुमानित लागत
$12.00
चरण
7
सामग्री
3

अधिक प्रयोग

कॉफी कप ऊष्मामिति 40 min कोल्ड पैक रसायन 20 min धातुओं की विशिष्ट ऊष्मा क्षमता 40 min बम ऊष्मामिति सिमुलेशन 45 min बर्फ की संलयन एन्थैल्पी 25 min मैग्नीशियम के दहन की गर्मी 50 min विघटन हमेशा ऊष्माक्षेपी नहीं होता 25 min सोडियम एसीटेट का ऊष्माक्षेपी क्रिस्टलीकरण 30 min हेस के नियम का सत्यापन 60 min

Frequently Asked Questions

What is the objective of ऊष्माशोषी अभिक्रिया प्रदर्शन?
एक नाटकीय रूप से ऊष्माशोषी अभिक्रिया प्रदर्शित करें जहां मिश्रण इतना ठंडा हो जाता है कि फ्लास्क के बाहर पानी जम जाता है।
How difficult is ऊष्माशोषी अभिक्रिया प्रदर्शन?
This experiment is rated as Intermediate (High School). It takes approximately 20 minutes to complete.
What safety precautions are needed for ऊष्माशोषी अभिक्रिया प्रदर्शन?
Key safety precautions include: Barium compounds are toxic if ingested; Ammonia gas is released — work in fume hood or ventilated area; Wear gloves when handling barium hydroxide.
What materials are needed for ऊष्माशोषी अभिक्रिया प्रदर्शन?
The main materials required are: Barium hydroxide octahydrate, Ammonium thiocyanate, Water.
What results should I expect from ऊष्माशोषी अभिक्रिया प्रदर्शन?
The temperature should drop to approximately -20°C within minutes. The flask should freeze to the wet board. A strong smell of ammonia confirms the reaction is proceeding.