Is the balloon that children play with hydrogen or helium?

Children play with hydrogen balloons, generally including rubber hydrogen balloons, plastic film hydrogen balloons and hydrogen balloons. Smaller hydrogen balloons are currently used for children's toys or festivals. ?

Hydrogen is a highly flammable, colorless, transparent, odorless and tasteless gas, which is insoluble in water. Its chemical formula is h? Hydrogen is the gas with the lowest known density and relative molecular weight in the world, which can be used as the filling gas for airships and hydrogen balloons. In February, 20 18, China realized the low-temperature preparation and storage of hydrogen, and won the top ten scientific progress in China in 20 17 of the Ministry of Science and Technology.

When conditions change (such as ignition, heating, using catalyst, etc.). ), the situation is different. For example, after hydrogen is adsorbed by metals such as palladium or platinum, its activity is very strong (especially palladium adsorption), and palladium has the strongest adsorption effect on hydrogen. When the volume fraction of air is 4%-75%, it will encounter a fire source and cause an explosion.

Physical properties:

Hydrogen is a colorless gas, and its density is lower than that of air. Under standard conditions, the mass of 1 liter of hydrogen is 0.0899g, which is also much lighter than air).

Because hydrogen is insoluble in water, it can be collected by drainage and gas collection. In addition, under the pressure of10/kpa, hydrogen can be transformed into a light blue liquid at -252.87℃ and a snow-like solid at -259. 1℃. At room temperature, the properties of hydrogen are very stable and it is not easy to react with other substances.

The above contents refer to Baidu Encyclopedia-Hydrogen.