Stoichiometry-Calculation involving Particle-moles-Mass

E.g
Zn+2HCl---->H2+ZnCl2
1how many grams of Zn are required to produce 6mole of hydrogen 
                   6molH2 x 1mol Zn    x  65.4g          =392g Zn
                                      1mol H2      1mole Zn




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C3H8+5O2---->3CO2+4H2O
a) What mass of CO2 is produced by reacting 3.00mole of O2?


3.00mol O2 x 3mol CO2   x  44.0g CO2    =79.2gCO2
                         5mol O2          1mol CO2
b)What mass of C3H8 is required to produce 100.0g of H2O?


100.0gH2O x 1mol H2O x 1mol C3H8 x 44.0gC3H8  =61.1g
                         18.0gH2O    4mol H2O     1mol C3H8


c) If a sample o propane is burned what mass of h2o is produced if the reaction also produces 50.0L of CO2 at STP? 

50.0L CO2 x 1mol CO2 x 4mol H2O x 18.0g H2O = 53.6g
                        22.4LCO2   3molCO2     1mol H2O
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