H2O2(1) --> H2O2(g)
Figure 1
Is this a physical or chemical reaction?

Physical reaction

Explanation:

Since there are no other chemicals in the equation, but the state of the chemical is going from a liquid to a gas, you can conclude that this is a physical reaction.

the mantle

explanation:

earth is divided into three layers: the crust or the outermost layer on which we live; the underlying, middle layer - the mantle - and the core (the innermost layer of earth).