Ch. 9 stochiometry                                          test                   30 points                                  chemistry

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.  You may use mathematica to do the “tedious” algebra.

1. In regards to the reaction:  20.0 g N2  +  excess H2  →   20.0 g NH3  [15 points; hint:  it’s a weekly quiz problem]

a. Write the balanced chemical equation

b. Assuming the percent yield is 100%, calculate the amount of NH3 produced in the reaction

c. What is the percent yield in the reaction ?

2. Solve   [15 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

c. 1.0 g Mg  +  __ grams HCl  →  H2  +  MgCl2