Chemistry
Grade-7
Easy
Question
Balloons are filled with a noble gas called _______________ that lets them float in the air.
- Neon
- Hydrogen
- Oxygen
- Helium
Hint:
The element after hydrogen.
The correct answer is: Helium
Helium balloons float because helium is less dense than air. The helium balloon deflates because the helium atoms are small enough to glide between the spaces of the balloon material. Helium balloons are made of Mylar, not rubber. This is because Mylar has less space between molecules, allowing the balloon to stay inflated.
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