Volumes of Gases and Balanced Equations pict Under s.t.p. one mole of a gas occupies 22.4 litres. 23 Hydrogen gas may be prepared by reacting zinc metal with dilute sulfuric acid. The following reaction occurs: Zn + H2SO, ZnSO. + H What volume of hydrogen gas at s.t.p. is evolved when 7 g of Zn are added to excess dilute sulfuric acid? How many moles of Hy would one mole of Zn produce? 10.05 A student is told to make 100 g of magnesium oxide by burning magnesium in excess oxygen. How much magnesium should the student burn? Magnesium reacts with oxygen according to the equation: 2Mg + O2 2Mgo (Mg = 24,0 = 16) Draw out a table under reaction! Write out all the information you have