Question

The complete combustion of 0.611 g of a snack bar in a calorimeter (Ccal = 6.15 kJ/°C) raises the temperature of the calorimeter by 1.29 °C. Calculate the food value (in Cal/g) for the snack bar.

Answer 1

Focus your attention to the units of the given data and the unit of the final measurement you're going to solve. Through dimensional analysis,you know that the working equation would be:

Food Value = CcalΔT/m
Food value = (6.15 kJ/°C)(1.29 °C)/0.611 g = 12.98 kJ/g

Convert kJ to cal (1 kJ = 239 cal)
Food value = 12.98*239 = 3,103.28 cal/g