Uh i think it is a balance combustion reaction not entirely sure tho
Burning a magnesium ribbon in the air is an addition reaction while heating potassium manganate 7 is a decomposition reaction.
<h3>Addition and decomposition reactions</h3>
Magnesium burns in air to produce magnesium oxide as follows:

Potassium manganate 7 burns to produce multiple products as follows:

Thus, the MgO will be heavier than Mg. On the other hand,
will be less heavy than
.
More on reactions can be found here: brainly.com/question/17434463
#SPJ1
Answer:
must be either a gas or liquid