To solve this question, we need to:
Step 1 - Transform the mass of Mg into moles using the following equation: moles = mass/molar mass
molar mass of Mg = 24 g/mol
Step 2 - use the stoichiometric ratio of the equation to discover the value in moles of MgO formed
Step 3 - Transform moles of MgO into grams using the following formula:
mass = moles x molar mass
molar mass of MgO = 40 g/mol
For trial 1:
Step 1:
moles = 0.312/24
moles = 0.013 moles
Step 2:
2 moles of Mg produce 2 moles of MgO
So 0.013 moles of Mg produce 0.013 moles of MgO
Step 3:
mass of MgO = 0.013 x 40
mass of MgO = 0.52 g
The theoretical yield of MgO in trial 1 is 0.52 g.
For trial 2:
Step 1:
moles = 0.412/24
moles = 0.0171666
Step 2:
2 moles of Mg produce 2 moles of MgO
So 0.0171666 moles of Mg produce 0.0171666 moles of MgO
Step 3:
mass of MgO = 0.0171666 x 40
mass of MgO = 0.68667
Answer: The theoretical yield of MgO in trial 1 is 0.52 g.
The theoretical yield of MgO in trial 2 is 0.68667 g.