Consider the balanced equation. 2hcl + mg mgcl2 + h2 if 40.0 g of hcl react with an excess of magnesium metal, what is the theoretical yield of hydrogen? 1.11 g 2.22 g 52.2 g 104 g

2Hcl + mg--->MgCl2 + H2

The theoretical yield of hydrogen is calculated as follows

calculate the moles of Hcl

mass/molar mass

40g/36.5=1.096 moles

by use of mole ratio of Hcl to H2 which is 2:1

moles of H2=1.096 / 2=0.548moles

mass is therefore = moles x molar mass

that is 0.548moles x 2 = 1.096 grams