Question

For each Mass of the following below, predict B for big, S for small, N for not effect base on a) to e):

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 Mg remained in final product

d) Some products come off on student's fingers while carrying the crucible, lid, and its contents to the balanced room.

e)Some MgN2 react with carbon monoxide to form MgO and N2 and C. Carbon gave product a gray color.

Predict each of the followings from a) to e) (for each):

- Mass of crucible, lid and metal

-mass of empty crucible and lid

- Mass of metal sample

- Mass of crucible, lid, contents after heating

- Apparent mass of MgO

- Percentage yield

Answer 1

a. Here the metal is Mg and the product is MgO , but MgO is a solid substance hence it has no effect N upon being warm during weighing.

b. BeO if present in the end product will drastically change the results B because the weight of BeO is different that of the MgO and hence the molar quantities cannot be correctly said. As a reult it may have large impact.

c. If small amount of Mg is present in the product then the result will change slightly S because the presence of Mg will change product weight slightly. Again the Mg can be separated from the end product easily.

d. If some product come off from the crucible lid on student`s finger then it will small change S because it will change the weight of the product by a small amount .

e. It will have a major change B in the weight of the product as because the Mg3N2 is forming the MgO so the correct weight of the product from the metal changes. Again the gray coloured C is very tough to separate from the product and it also gives a change in the weight of the product.