A Big Mac hamburger from McDonald’s contains 540 Calories. (a) How many kilojoules does a Big Mac contain? (b) For how many hours could the amount of energy in a Big Mac light a 100 watt light- bulb? (1 watt = 1 J/s)

##2259.36 kJ## ##6## hours and a half (almost)

Considering that ##1 Cal=4.186 kJ=4184 J## then ##540 Cal =540xx4184=2259360 J=2259.36 kJ##. Your light bulb needs ##100J## each second so if you have ##2259360 J## it can operate for ##2259360/100=22593.6 s=6.276 hr##