Question

The heat of combustion of fructose C6H12O6 IS -2812KJ / mol. It a fresh Golden delicious apple (120g) contains 16g of fructose , What caloric contens does the fructose contribute to the apple ?

Answer 1

Fructose contributes with approximately 250 kJ of caloric content for a golden apple.

The first thing we need to do is calculate the molar mass of fructose (C6H12O6), using the following atomic masses:

C: 12 u

H: 1 u

O: 16 u

molar mass = (6 * 12) + (12 * 1) + (6* 16) = 180 g/mol

From the problem, we know that each mol of fructose releases 2812 kJ, and the question is: how much energy does 16g of fructose release? With that in mind, we can write:

180g C6H12O6 ---------- 2812 kJ

16g C6H12O6 ---------- x (kJ)

Solving for x, we have that that fructose contributes with approximately 250 kJ to the caloric content of a golden apple.