How will the relative number of moles of Mg and O be affected if the following procedural errors are made? Briefly explain
(1) the crubile is not brought to constatn mass before the Mg is added.
(2) water is not added after the first heating of Mg, and the entire solid in the crucible is considered to be magnesium oxide.
(3) some of the fluffy white precipiate is lost before the crucible is weighed for the last time.
(4) In an effort to begin a second while the first is cooling, the hot crucible containing the solid from determination 1 is accidently dropped, and a small chip is lost from the crucible.
(1) If the crucible is not brought to a constant mass before adding the Mg, it means that there might be some impurities or residual substances present in the crucible. These impurities would contribute to the mass measured later on. This would result in an inflated mass measurement, leading to an incorrect calculation of the number of moles of Mg. However, the number of moles of O would not be directly affected by this error.
(2) If water is not added after the first heating of Mg and the entire solid in the crucible is considered to be magnesium oxide, this would result in an incorrect calculation of the number of moles of Mg. The subsequent mass measurement would include the mass of unreacted Mg, resulting in an overestimated mass for MgO. Consequently, the number of moles of Mg would be higher than the actual value. The number of moles of O would remain unaffected by this specific error.
(3) If some of the fluffy white precipitate is lost before the crucible is weighed for the last time, it means that the measured mass would not accurately represent the mass of the magnesium oxide. This error would lead to an underestimation of the mass of MgO. Consequently, the number of moles of Mg and O would be underestimated.
(4) If the hot crucible containing the solid from determination 1 is accidentally dropped and a small chip is lost from the crucible, it means that some of the MgO may have been lost. This loss would result in a smaller measured mass of MgO, leading to an underestimation of the number of moles of Mg and O.
Overall, these procedural errors can lead to inaccuracies in the measured masses, resulting in incorrect calculations of the number of moles of Mg and O in the magnesium oxide.