what mass of propane must undergo complete combustion to produce 150 000kj of heat? the molar enthalpy of propane is -2219.2kj/mol?

2980.4g (or, approx. 3000g, rounded off to the correct number of significant figures)

Step-by-step explanation

Molar mass of propane (C3Hg) is given by = (3 x 12. 01) + (8 x 1. 008) = 44. 094 g/mol. Given that, the molar enthalpy of combustion of propane is -2219.2 kJ/mol. This means that the combustion of 1 mol of propane produces 2219.2 kJ of energy! 1 mol propane = 44.094g propane, and, We have to produce 150 000 kJ of heat. So, the mass of propane required = 150, 000 kJ x 1 mol propane X 44.094g propane 2219.2 kJ 1 mol propane = 2980. 398g ~ 2980. 4g propane.

Hence, 2980.4g (or, approx. 3000g, rounded off to correct number of significant figures) of propane should be  completely combusted to produce 150,000 kJ of heat.