Mass number is the number of protons and neutrons in an atom, and it tells us about the mass of the atom in amu, or atomic mass units. Atomic mass is the average mass of all the isotopes of a certain type. It is a weighted average that takes into account the abundances of all of the different isotopes
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Answer:
1.645 moles of excess reactant that is of magnesium metal are left over.
Explanation:
Moles of magnesium metal = 3.29 mol
Moles of HCl = 3.29 mol

According to recation, 2 moles of HCl reacts with 1 mol of magnesium metal, then 3.29 moles of HCl will react with :
of magnesium metal
Moles of HCl left = 3.29mol - 3.29 mol = 0
Moles of magnesium metal left = 3.29 mol - 1.645 mol = 1.645 mol
1.645 moles of excess reactant that is of magnesium metal are left over.
<h2>b is the correct answer</h2>
according In my course I studying it all
C or A I may be incorrect but those are what I think it is
Diphosphorus tetraiodide is a covalent compound.
It has low melting point as compared to ionic compounds
It is a rare compound where the oxidation state of Phosphorous is +2.
It is also termed as subhalide of phosphorous.