Question

A student was tasked to perform gravimetric analysis of a soluble sulfate. His unknown sample weighed 0.7543 g. The sample underwent precipitation using BaCl2 and was digested for overnight. The precipitate was then filtered off to obtain white crystalline precipitate that was collected in an ash less filter paper. In performing constant weighing, he obtained a crucible mass that is 29.9442 g. After burning his samples inside the crucible, the obtained mass was 30.3375 g.

Questions:
Compute for the experimental mass (g) of SO3 in grams obtained by the student. A) 0.1439 B) 0.1349 C) 0.1943 D) 0.1394 E) 0.3591

Compute for the experimental % SO3 obtained by the student.
A) 73.21 B) 56.33 C) 17.89 D) 56.89 E) 72.80

Compute for the theoretical % SO3 obtained by the student
A) 0.3933 B) 56.37 C) 17.33 D) 17.89 E) 0.4252

Compute for the % error of the student in his analysis.
A) 53.67 B) 68.27 C) 75.43 D) 11.34 E) 42.52

Answer 1

I just need answers even without computations, please help

Answer 2

Ah! You just want answers. You don't want to know how to work the problem.

Answer 3

30.3375 g = mass xble + mass ppt
-29.9442 g = mass xble
------------------------------------------------------
....0.3933 = mass ppt = mass SO3

experimental % SO3 in the sample = 0.3933 x (molar mass SO3/molar mass BaSO4)*100 = ? %SO3

I don't know how to answer the last two because I don't know the %SO3 in the unknown. You are looking for theoretical % and % error and I don't know how you calculate that without knowing % SO3 in the unknown. I answered a similar question a few days ago and I had the same problem. The trouble may be because of the word "theoretical" so it may be a language problem.