S140: Chemical Rxns – Combustion – H2 and He Balloon Explosions

Introduction

A balloon filled with helium and one filled with hydrogen are ignited.  Hydrogen provides a loud explosion and flame. 

He(g) + O₂(g) → N.R.
2H₂(g) + O₂(g) → 2H₂O(g)

To Conduct Demonstration

1. Light the candle on the end of the yardstick and lower the lights.
2. Bring the candle under the helium balloon until the tip of the flame touches the balloon.  Be prepared for an explosion. Do not light the string on fire!
3. Repeat with the hydrogen balloon.  The explosion will be much more violet.

Demo Time: ~2 minutes

Safety 

Hearing damage can occur with especially large balloons or small rooms.  Earplugs or ear protectors maybe worm.

Acknowledgment

Margaret Asirvatham & Lyn Pierce, Summer 1987Lora Ruffin and Michael Polk, Summer 2009