BIO Entropy Change from Digesting Fat. Digesting fat produces 9.3 food calories per gram of fat, and typically 80% of this energy goes to heat when metabolized. (One food calorie is 1000 calories and therefore equals 4186 J.) The body then moves all this heat to the surface by a combination of thermal conductivity and motion of the blood. The internal temperature of the body (where digestion occurs) is normally 37°C, and the surface is usually about 30°C. By how much do the digestion and metabolism of a 2.50-g pat of butter change your body’s entropy? Does it increase or decrease?
Solution 39P Step 1: In this question, we need to find the change in entropy and also check if the entropy decreases or increases One food calorie = 1000 calories or 4186 J Heat transferred to body by digestion of 2.5 g fat is We have 9.3 food calories per gram of fat 80 % to metabolism Hence we get heat transferred as Q = 0.8 × 2.5 g × 9.3 × 4186 J Q = 77859.6 J