Answer to Question #257689 in General Chemistry for Maddy

Question

n average hot water tank will hold 300.0 L of water and needs to be kept at 65 degrees celsius in order to kill any bacteria in the water. If you are filling a new tank with water at a starting temperature of 12.5 degrees celsius, what mass of natural gas (methane, CH4) must be burned in a complete combustion reaction in order to bring your tank up to the correct temperature? The specific heat capacity for water is 4.184. J/g °C. The balanced equation for the complete combustion of methane is: CH4 (g) + 2O2(g) --> CO2(g) + 2H2O(g) 

Answer 1

$\Delta\Tau×C_ water×m_ water=\Delta H_r (entalpy) ×\nu(CH_4)$

m(H2O)=Volume(H2O)×p=300kg

DT=-52,5×C

Hr=-802kJ/mole

Cwater=4,2kJ×C^-1×kg^-1

V(CH4)=82.5 moles