One reaction that produces hydrogen gas can be represented by the following unbalanced chemical equation: mg(s) + hcl(aq) → mgcl2(aq) + h2(g)
a. what mass of hcl is consumed by the reaction of 2.50 moles of magnesium?
b. what mass of each product is produced in part (a)?

A. 182.3 grams of HCl, are consumed.

B. The reaction produce 5 g of H₂ and 238 g of MgCl₂

Explanation:

This the balanced equation:

Mg (s)  + 2HCl (aq) →    MgCl₂(aq) + H₂(g)

Ratio between Mg and HCl is 1:2, so if I react 2.5 moles of Mg, I use the double of moles, of Hydrochloridric (5 moles)

Molar mass of HCl = 36.46 g/m

Mass = Moles . Molar mass

Mass = 5 m . 36.46 g/m →  182.3 g

In this case, we have no limiting reactant and nothing is in excess. It is the same for the calculations to do the rule of three.

1 mol of Mg makes 1 mol of MgCl₂

2.5 moles of Mg makes 2.5 moles of MgCl₂

2 mol of HCl makes 1 mol of MgCl₂

5 moles of HCl makes 2.5 moles of MgCl₂

In conlussion, this reaction makes 2.5 moles of MgCl₂ and 2.5 moles of H₂

Molar mass H₂ = 2 g/m

Molar mass MgCl₂ = 95.2 g/m

2.5 moles . 2 g/m = 5 g H₂

2.5 moles . 95.2 g/m = 238 g MgCl₂

it is the most commonly accepted one