Question

4) What mass of natural gas (CH4) must burn so that the heat released by the reaction CH4(g)2 O2(g) CO2(g)+2 H20(g) is 267 kJ. The molar mass of CH4 is 16.0 g mol. The standard enthalpies of formation of some of the substances in the reaction are: AH (CH (g))-74.81 kJ mol AH (CO2(g)-393.509 kJ mol AHP(H20(g)-241.818 kJ mol a) 0.223 g b) 3.57 g c) 0.280 g d 0.623 g e) 1195 g f) 467 g

Answer 1

CH4(g) + 2O2(g) -----------> CO2(g) + 2H2O(g)       $\Delta$ H⁰rxn   = -267KJ

$\Delta$H⁰rxn   = $\Delta$ H⁰f products - $\Delta$ H⁰f reactants

                = 2*-241.818-393.509 -(-74.81+ 2*0)

                = -802.335KJ/mole

-802.335 KJ of heat energy is released form 1 mole of CH4

-802.335 KJ of heat energy is released form 16g of CH4

-267KJ of heat energy is released from = 16*267/802.335

                                                               = 5.32 g of CH4

correct answer is 5.32g of CH4

But in this optional no correct answer