Phollobrova YABA COLLEGE OF TECHNOLOGY
SCHOOL OF SCIENCE
DEPARTMENT OF CHEMICAL SCIENCE
2M SEMESTER EXAMINATIONS 2016/2017 SESSION
PAPER CODE:
ISTRY
TIME:2 HRS
COURSE UNIT
iting, writing or any other inscription on your question paper, except name and registration number where necessary.
ROHIBITED IN THE EXAMINATION HALL ATTEMPT 2 IN SECTION A AND 2 QUESTIONS IN SECTION B
4
T and Z are two elements which form T2Zz and TZ, molecules. If 0.1 mole
of T2Z; and TZ2 weighs 16.9 g and 10.3 g respectively. What are the
atornic mass of T and Z?
If 9.45 g of X element contains 9.03 x 1022 atoms and 0.1 mole of X2Y2
compound is 16 g. Find the atomic mass of Y element.
ne the following terms
Theoretical vield

Which supports the idea that birds and butterflies both have wings but they do not have a common ancestor with wings? a. the wings are analogous structures that evolved differently and do not have a similar internal structure. b. the wings are homologous structures that evolved differently and do not have a similar internal structure. c. wings of birds are vestigial structures, but the wing structures of bats are not vestigial. d. wings of bats are vestigial structures, but the wing structures of birds are not vestigial

Electric charge is what ? a. kinetic energy b. radiation c. discovery d. electricity

These questions are based on the attached photo. the experiment is about burning magnesium metal with oxygen. 1. write the balanced chemical equation for the reaction you are performing. 2. calculate the mass of magnesium metal used in each trial. o trial 1: o trial 2: 3. calculate the actual yield of magnesium oxide for each trial. o trial 1: o trial 2: 4. magnesium is the limiting reactant in this experiment. calculate the theoretical yield of mgo for each trial. o trial 1: o trial 2: 5. determine the percent yield of mgo for your experiment for each trial. o trial 1: o trial 2: 6. determine the average percent yield of mgo for the two trials. your company currently uses a process with a similar cost of materials that has an average percent yield of 91 percent. if the average percent yield of this process is higher than that, this could save the company money. what is your recommendation to the company? support your recommendation using your data, calculations, and understanding of stoichiometry gathered from this lab.