This equation shows that 1 mole of MgCl2 and 1 mole of H2 will be produced with 1 mole of Mg and 2 moles HClTherefore 10.0g Mg(s) + 20.0g HCl(aq) reacts to create 30.0g (MgCl2(aq) + H2(g))Atomic weight of CL: 35.453g/molAtomic weight of H: 1.00794g/molTherefore 1 mol HCL = 1.......
Hope this helped. As I said, it's been a while since I've been in chemistry but this helped me recall it easily.
Stoichiometry is founded on the law of conservation of mass: the mass of the reactants equals the mass of the products.
This equation shows that 1 mole of MgCl2 and 1 mole of H2 will be produced with 1 mole of Mg and 2 moles HCl
Therefore 10.0g Mg(s) + 20.0g HCl(aq) reacts to create 30.0g (MgCl2(aq) + H2(g))
Atomic weight of CL: 35.453g/mol
Atomic weight of H: 1.00794g/mol
Therefore 1 mol HCL = 1.00794 + 35.453 = 36.46094g
20.0g HCl * (1 mol HCL/36.46094g HCL) = 0.5485 mol HCL
Since it reacts completely, as stated, 0.5485 mol HCL will create (1/2)(0.5485) mole H2. Recall 1 mole of MgCl2 and 1 mole of H2 will be produced with 1 mole of Mg and 2 moles HCl.
0.2743 mole H2 * (2.01588g H2/1 mol H2) = 0.5530g H2
**Usually gas is measured in liters and if asked to compute, use the equation PV = nRT**
P = absolute gas pressure
V = gas volume
n = number of moles
R = universal ideal gas law constant
T = absolute gas temperature
