What mass of natural gas {rm{(CH}}_4 ) must you burn to emit 276 kJ of heat?

What mass of natural gas {rm{(CH}}_4 ) must you burn to emit 276 kJ of heat?begin{array}{l} {rm{CH}}_4 (g); + ;2{rm{ O}}_2 (g); rightarrow ;{rm{CO}}_2 (g); + ;2{rm{ H}}_2 {rm{O(}}g) {rm{ }}Delta {kern 1pt} H_{{rm{rxn}}}^circ = – 802.3;{rm{ kJ}} end{array}