Yes, if you combust the chocolate to extract all chemical energy from it, and have a machine with perfect energy efficiency, then you can lift 100 kilograms 2.4 kilometers high. But your body is rather far from a machine with perfect energy efficiency. (Your heart needs to pump, your diaphragm goes up and down, in addition to other mechanical and chemical "inefficiencies".)
For example, doing a google search brings up this study which studies aerobic weight lifting exercises (so presumably the weight is much less than 100 kilograms, though distance is about the same). The measured total aerobic energy consumption (from carbon dioxide content of the exhaled breath) is around 10 kilojoules mer minute. For that exercise, your 100 grams of chocolate can sustain you for around 4 hours. (If you were to do 4800 reps in 4 hours, that would require sustaining 20 reps a minute, a truly fearsome rate...)
If you look at the basal metabolic rate for humans, say we have a typical male standing at 170 centimeters, 75 kilograms, and 30 years of age, he would burn about 1600 kilocalories per day doing absolutely nothing. So a 100g chocolate bar gets him through about a third of the day.
