흡열 반응 실험

수산화바륨과 티오사이안산암모늄의 냉각 반응

Thermochemistry Intermediate (High School) 20 분 ~$12.00

목표

혼합물이 플라스크 외부의 물을 얼릴 만큼 차가워지는 극적인 흡열 반응을 실증한다.

배경

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.

안전 경고

  • 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

필수 개인 보호 장비

goggles gloves lab_coat

재료

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

장비

250 mL Erlenmeyer flask Wooden board Thermometer Stirring rod

실험 절차

1

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

1 분
2

Add 32 g barium hydroxide octahydrate to the flask.

2 분 Wear gloves — barium is toxic
3

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

2 분 Ammonia released — ventilation
4

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

1 분
5

Observe the temperature dropping dramatically. Record the minimum temperature.

5 분 Do not inhale fumes
6

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

2 분
7

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

2 분

예상 결과

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.

정리

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

세부 정보

카테고리
Thermochemistry
난이도
Intermediate (High School)
소요 시간
20 분
예상 비용
$12.00
단계
7
재료
3

더 많은 실험

아세트산나트륨의 발열 결정화 30 min 마그네슘의 연소열 50 min 금속의 비열 용량 40 min 커피컵 열량 측정 40 min 헤스의 법칙 검증 60 min 얼음의 융해 엔탈피 25 min 용해는 항상 발열이 아니다 25 min 냉찜질 팩의 화학 원리 20 min 폭탄 열량계 시뮬레이션 45 min

Frequently Asked Questions

What is the objective of 흡열 반응 실험?
혼합물이 플라스크 외부의 물을 얼릴 만큼 차가워지는 극적인 흡열 반응을 실증한다.
How difficult is 흡열 반응 실험?
This experiment is rated as Intermediate (High School). It takes approximately 20 minutes to complete.
What safety precautions are needed for 흡열 반응 실험?
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 흡열 반응 실험?
The main materials required are: Barium hydroxide octahydrate, Ammonium thiocyanate, Water.
What results should I expect from 흡열 반응 실험?
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.