g Which of the following describe chemical properties of hydrogen gas (H2)? At room temperature its density is less than any other gas. It reacts vigorously with oxygen to form water. Liquefied H2 boils at a very low temperature (-253oC). Both b and c are chemical properties.

It reacts vigorously with oxygen to form water.

Explanation:

Physical property is defined as the property of a substance which becomes evident during physical changes.

Example:  At room temperature its density is less than any other gas.

Liquefied boils at a very low temperature  

Chemical property is defined as the property of a substance which becomes evident during chemical changes. These properties are defined when  a substance undergo changes in bonding of atoms.

Example:  It reacts vigorously with oxygen to form water.

geosphere and hydrosphere.

this is because the geosphere has to do with geological events, while the hydrosphere controls all water on earth.