Ch. 9  balancing chemical equation / stoichiometry                 test [60 points]            Chem

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.  [16 points]

1. Balance the following chemical equations using the lowest ratio of integers; if the coefficient is one, then write “1”.  [20 points]

a.  ___ CH3OH  +  ___  O2  →   ____  CO2  +   ___ H2O

b.  ____  CaCl2  +  ___  Li3PO4  →  ___  Ca3(PO4)2  +  ____  LiCl

c.  ___  C12H22O  +  ___  O2  →  ___  H2O  +  ___ CO2

d. ___  Co(NO3)3  +  ___ (NH4)2S  →  __  Co2S3  +  ___  ammonium nitrate

e. Cellular respiration, i.e. combustion of glucose, C6H12O6: ___________  

2. 10.0 grams of calcium chloride, CaCl2, reacts with excess lithium phosphate, Li3PO4,  to form lithium chloride, LiCl, and  ___ grams of calcium phosphate, Ca3(PO4)2 .  [10 points]

3. 25.0 grams of calcium chloride, CaCl2, reacts with 25.0  grams of lithium phosphate, Li3PO4,  to form lithium chloride, LiCl, and  ___ grams of calcium phosphate, Ca3(PO4)2 .  [15 points]

4. What is the % yield in the reaction:  10.0 g H2  +  excess N2  →  45.0 g NH3  ?   [15 points]