Conceptual Challenge Problems These rigorous, thought-provoking problems integrate conc...

Conceptual Challenge Problems

These rigorous, thought-provoking problems integrate conceptual learning with problem solving and are suitable for group work.

CP19.B (Section 19.4) People obtain energy by oxidizing food. Glucose, a typical foodstuff, is a carbohydrate. When metabolized, glucose is oxidized to water and carbon dioxide.

The heat of combustion of glucose is 2.80 × 10³ kJ/mol, which means that as glucose is oxidized, its electrons lose 2.80 × 10³ kJ/mol as they give up potential energy in a complicated series of chemical steps.

(a) Assume that a person requires 2400 food Calories per day and that this energy is obtained from the oxidation of glucose. How much O₂ must a person breathe each day to react with this much glucose?

(b) Each mole of O₂ requires 4 mol electrons, regardless of whether the O atoms become part of CO₂ or H₂O. What would be the average electric current (C/s) in a human body using the above amount of energy described in part (a) per day?

(c) Use the answer from part (b) and calculate the electrical potential this current flows through in a day to produce the 2400 food Calories. (1 Calorie = 4.18 kJ)