Answer is: because carbon(IV) oxide is released.
For example if baking soda is used for <span>the pizza dough, than on heat carbon(IV) oxide is product of chemical reaction:
2NaHCO</span>₃ → Na₂CO₃ + CO₂ + H₂O.
If we use yeast (<span>single-celled microorganism)</span>, also carbon(IV) oxide produced, because yeast turns sugars into carbon(IV) oxide.
You would get four moles of magnesium nitrate :) you would have to
“ ?molesmg(oh)2 = 8molmg(no3)2 x molmg(oh)2 / 2molhno3 = 4 moles of magnesium nitrate :))) hopefully this helps! <3