Final answer:
To find the actual yield of magnesium nitrate from magnesium and excess copper (II) nitrate, calculate the theoretical yield using the molar masses and stoichiometry from the balanced chemical equation, then apply the given efficiency (30.40%) to the theoretical yield.
Step-by-step explanation:
To calculate the actual yield of magnesium nitrate formed from the reaction of magnesium with excess copper (II) nitrate, we first have to find the theoretical yield using a mass-mass calculation.
First, we need to write down the balanced chemical equation for the reaction. Assuming the formation of magnesium nitrate involves magnesium reacting with nitric acid, the reaction can be represented by:
3 Mg(s) + 2 Cu(NO₃)₂(aq) → 3 Mg(NO₃)₂(aq) + 2 Cu(s)
Now, using the molar mass of magnesium (24.31 g/mol) and magnesium nitrate (Mg(NO₃)₂, 148.31 g/mol), we carry out the mass-mass calculation as follows:
111.8 g Mg x (1 mol Mg / 24.31 g Mg) x (1 mol Mg(NO₃)₂ / 1 mol Mg) x (148.31 g Mg(NO₃)₂ / 1 mol Mg(NO₃)₂)
This gives us the theoretical yield of magnesium nitrate. To find the actual yield, we take the efficiency of the reaction, which is given as 30.40%, and apply it to the theoretical yield:
Actual yield = Theoretical yield x (Efficiency/100)
Lastly, we calculate the percent yield by comparing the actual yield to the theoretical yield using a similar formula to:
Percent yield = (Actual yield / Theoretical yield) x 100%