Question

Mass of crucible, lid, Mg turning: 21.8096 g Mass empty crucible and lid: 21.6585g Mass of Magnesium used: 0.1507 g Mass of crucible, lid, and product: 21.8844 g Apparent mass of Magnesium oxide: 0.2259 g Predict the effect of the following. Mark B for too big, S for too small, N for no effect, ? for impossible to predict: a. The crucible, lid and products were warm when weighted b. The Beryllium end up BeO (mass metal sample was correctly determined) c. Some unreacted Magnesium remained in final product d. Some products came off on the students fingers while carrying the crucible, lid and its contents to the balance room e. Some Mg3N2 react with CO form MgO and N2 and C. Carbon gave product a gray color. e.

Answer 1

a. The crucible ,lid and product were warm when weighed- N - because MgO is a solid substance and it has no effect on the weight of MgO.

b. B- because the BeO have separate molar weight and the molar quantities cannot be correctly determined if there is any BeO present.

c.S- because if there is some unreacted Mg it can separated so it will not cause much change to the experimental setup.

d. S- because if some of the product came off then there will be small change in the experimental weight of the product.

e. B- because the N2 will come out again the gray coloured C will give some weight some it is hard to get the original weight