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
.
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Iron rusts when exposed to air → chemical property
Answer: This is known as substitution cipher.
Explanation:
Mass of Li = 237.38 g
<h3>Further explanation</h3>
The mole itself is the number of particles contained in a substance amounting to 6.02.10²³

<h3>Known</h3>
Moles of Li = 34.2
Molar mass(MW) of Li = 6.941 g/mol
then mass of Lithium (Li) :
