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Jumat, 06 Januari 2012

REAL LIFE STOICHIOMETRY

1.   Airbag Design
     
     Assume that 65.1 L of N2 gas are needed to inflate an air bag to the
     proper size.  How many grams of NaN3 must be included in the gas
     generant to generate this amount of N2
     (Hint:  The density of N2 gas at this temperature is about 0.916 g/L).
              NaN3(s)  --->    Na(s)  +   N2(g)
              Na(s)  +  Fe2O3(s) --->   Na2O(s) +  Fe(s) 

2.   Water from a Camel

     Camels store the fat tristearin (C57H110O6) in the hump.  As well as
     being a source of energy, the fat is a source of water, because when
     it is used the reaction take place,
            2 C57H110O6(s)  +  163 O2(g)  ---> 114 CO2(g)  +  110 H2O(l)
     What mass of water can be made from 1.0 kg of fat?

3.  Water in Space  

     In the space shuttle, the CO2 that the crew exhales is removed from the
     air by a reaction within canisters of lithium hydroxide.  On average, each
     astronaut exhales about 20.0 mol of CO2 daily.  What volume of water will
     be produced when this amount of CO2 reacts with an excess of LiOH?
    (Hint:  The density of water is about 1.00 g/mL.)
                     CO2(g)  +   LiOH(s)  ---->  Li2CO3(aq)  +  H2O(l)

4. Rocket Fuel
   
    The compound diborane (B2H6) was at one time
    considered for use as a rocket fuel.  How many grams
    of liquid oxygen would a rocket have to carry to burn
    10 kg of diborane completely? 
   (The products are B2O3 and H2O).
                 B2H6  +  O2 ----->   B2O3 + H2O      
   

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