In a magnesium oxide experiment
Describe the effect of the following factors, whether decrease, increase, or has no effect on the reported value of Mg to O mole ratio:
a) if carbon is deposited on the crucible's surface(due to improper heating) and the crucible with contents is weighed without removing the carbon residue.
b) if the magnesium oxide ash is not dried completely.
c) if rapid oxidation of magnesium occurs by too much air, and some Mg is lost.
d) if air is not allowed sufficiently to react with Mg.
See above
a) If carbon is deposited on the crucible's surface (due to improper heating) and the crucible with contents is weighed without removing the carbon residue, the reported value of the Mg to O mole ratio will be increased. This is because the carbon residue will add additional mass to the crucible, resulting in an overestimate of the magnesium content in the compound.
b) If the magnesium oxide ash is not dried completely, the reported value of the Mg to O mole ratio will be increased. This is because the presence of residual moisture will add additional mass to the compound, resulting in an overestimate of the magnesium content.
c) If rapid oxidation of magnesium occurs by too much air, and some Mg is lost, the reported value of the Mg to O mole ratio will be decreased. This is because some magnesium is lost during the oxidation process, leading to an underestimate of the magnesium content in the compound.
d) If air is not allowed sufficiently to react with Mg, the reported value of the Mg to O mole ratio will be decreased. This is because insufficient air will result in incomplete oxidation of magnesium, leading to an underestimate of the magnesium content in the compound.
a) If carbon is deposited on the crucible's surface and the crucible with contents is weighed without removing the carbon residue, it will have an effect on the reported value of the Mg to O mole ratio. This is because the carbon residue will contribute to the weight measured during the experiment, thus increasing the measured mass of the crucible and its contents. As a result, the reported value of the Mg to O mole ratio will be higher than the actual value.
To obtain an accurate measurement of the Mg to O mole ratio, it is necessary to remove the carbon residue before weighing the crucible with the contents. This can be done by heating the crucible in a suitable manner to burn off the carbon before weighing.
b) If the magnesium oxide ash is not dried completely, it will have an effect on the reported value of the Mg to O mole ratio. This is because the presence of moisture in the ash will contribute to the weight measured during the experiment, leading to an artificially higher mass of magnesium oxide.
To minimize this effect, the magnesium oxide ash should be thoroughly dried before weighing. This can be achieved by heating the ash at a suitable temperature for a sufficient duration to remove any moisture present.
c) If rapid oxidation of magnesium occurs due to too much air and some Mg is lost, it will have an effect on the reported value of the Mg to O mole ratio. This is because the loss of magnesium will lead to a lower measured mass of magnesium oxide, resulting in a lower reported Mg to O mole ratio.
To mitigate this effect, it is important to control the amount of air or oxygen present during the experiment. This can be achieved by using a lid or covering the reaction vessel to limit the exposure of magnesium to excessive air.
d) If air is not allowed sufficiently to react with Mg, it will have an effect on the reported value of the Mg to O mole ratio. Insufficient air will result in incomplete oxidation of magnesium, leading to a lower measured mass of magnesium oxide and therefore a lower reported Mg to O mole ratio.
To ensure sufficient air access, it is important to provide adequate ventilation or oxygen supply during the experiment. This can be achieved by using an appropriate setup that allows air to circulate around the magnesium sample, ensuring complete oxidation.