A__is a large explosion of a collasping supergiant star which occurs when fusin stops.

...~ While this is happening, the core collapse is halted when it becomes neutron degenerate matter — a white dwarf on steroids, so to speak. This causes the infalling layers to rebound in a massive shock front that rips the star apart in the colossal explosion we call a supernova ~...

-Koko

Explanation:And when the helium ignites, the outer layers of the star are blown off in huge clouds of gas and dust. Once a star stabilizes after it forms, it spends most of its lifetime in a state of dynamic equilibrium. ... Once the star depletes the available hydrogen in the core, the fusion stops, and the star begins to collapse.

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2h2o2--> 2h2o + o2

this reaction is of the spontaneous decomposition of hydrogen peroxide down into water and oxygen.

add 2 molecules of hydrogen peroxide and 2 molecules of water. since oxygen is naturally diatomic, the total number of atoms of each element is now the same on both sides of the equation so it is balanced.

this may not be entirely correct but let me know.