Ch. 9 stochiometry      test                  40  points                                             chemistry

In problems involving any calculation, show your work in an organized manner, include (i) any relevant equation (or formula), (ii) conversion factor(s), (iii) put the proper units in your calculations and answer, and (iv) have the proper number of significant figures in your answer.

1. In regards to the chemical  reaction:  C2H6  +  O2  →   CO2  + H2O  [15 points; weekly quiz problems]

a. write the balanced chemical equation

b.  fill-in the blank:  5.0 g C2H6  +  excess O2  →  ___ g CO2  + H2O

c. fill-in the blank:  15.0 g C2H +  35.0 g O2  →  ___ g CO2  + H2O

2. Solve   [2014 – 2015 test; 10 points]
a. 3.0 moles CH3CH3  +  excess O2 →  carbon dioxide  +  __ moles water

b.  2.0 moles Ca(NO3)2  +  excess K3PO4  →  Ca3(PO4)2  +  __  grams KNO3

3.  5.0 g hydrogen gas reacts with excess nitrogen gas to form ammonia, NH3.  If the percent yield in the reaction is 88%, how many grams of ammonia was produced in the reaction ?  [2015 – 2016 test; 15 points]