If you start with 30.0 grams of sodium fluoride, how many grams of magnesium fluoride will be produced?

22.2 g of MgF₂

Explanation:

We star from the reaction:

NaF → sodium fluoride

Mg → Magnesium

2NaF  +  Mg →  MgF₂  +  2Na

2 moles of sodium fluoride react to 1 mol of Mg in order to produce 1 mol of magnesium fluoride and 2 moles of sodium.

We convert mass of the reactant to moles:

30 g . 1mol / 41.98 g = 0.715 mol

We assume that Mg is in excess

As ratio is 2:1, if we have 0.715 moles of NaF we may produce the half of moles, of MgF₂

0.715 mol /2 = 0.357 moles of MgF₂

We convert moles to mass: 0.357 mol . 62.30g /mol = 22.2 g

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