Idon’t know how to calculate reacting masses

Mass of phosphoric acid = 6.37 g

Mass of magnesium nitride = 50.5 g

Mass of  iron chloride = 22.71 g

Explanation:

1 = Given data:

Mass of phosphorus = 4 g

Mass of phosphoric oxide = ?

Solution:

4P +  5O₂  →  2P₂O₅

Number of moles of phosphorus = mass / molar mass

Number of moles of phosphorus = 4 g / 31 g/mol

Number of moles of phosphorus = 0.13 mol

Mole ration of phosphorus and phosphoric acid.

                                 P        :         P₂O₅

                                 4        :           2

                               0.13      :          2/4× 0.13 = 0.065 mol

Mass of phosphoric acid:

Mass of phosphoric acid = moles × molar mass

Mass of phosphoric acid = 0.065 mol × 98 g/mol

Mass of phosphoric acid = 6.37 g

2 = Given data:

Mass of magnesium = 36 g

Mass of magnesium nitride = ?

Solution:

3Mg  + N₂   →   Mg₃N₂

Number of moles of magnesium = mass / molar mass

Number of moles of magnesium = 36 g / 24 g/mol

Number of moles of magnesium = 1.5 mol

Mole ration of magnesium and magnesium nitride.

                                 Mg     :        Mg₃N₂

                                 3        :           1

                               1.5        :          1/3× 1.5 = 0.5 mol

Mass of magnesium nitride:

Mass of magnesium nitride = moles × molar mass

Mass of magnesium nitride = 0.5 mol × 101 g/mol

Mass of magnesium nitride = 50.5 g

3 = Given data:

Mass of iron = 8 g

Mass of iron chloride = ?

Solution:

2Fe  + 3Cl₂   →   2FeCl₃

Number of moles of iron = mass / molar mass

Number of moles of iron = 8 g / 55.85 g/mol

Number of moles of iron = 0.14 mol

Mole ration of iron and iron chloride.

                                Fe     :        FeCl₃

                                 2        :           2

                               0.14       :          0.14

Mass of iron chloride:

Mass of  iron chloride = moles × molar mass

Mass of iron chloride = 0.14 mol × 162.2 g/mol

Mass of  iron chloride = 22.71 g

b is the correct