Skip to main content
Ch.5 - Thermochemistry
Chapter 5, Problem 99

At the end of 2020, global population was about 7.8 billion. What mass of glucose in kg would be needed to provide 1500 Cal/person/day of nourishment to the global population for one year? Assume that glucose is metabolized entirely to CO2(𝑔) and H2O(𝑙) according to the following thermochemical equation: C6H12O6(s) + 6 O2(𝑔) β†’ 6 CO2(𝑔) + 6 H2O(𝑙) Ξ”HΒ° = -2803 kJ

Verified Solution

Video duration:
5m
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Stoichiometry

Stoichiometry is the branch of chemistry that deals with the quantitative relationships between the reactants and products in a chemical reaction. It allows us to calculate the amounts of substances consumed and produced in a reaction based on balanced chemical equations. In this question, stoichiometry is essential for determining how much glucose is needed to meet the caloric requirements of the global population.
Recommended video:
Guided course
01:16
Stoichiometry Concept

Caloric Value of Glucose

The caloric value of glucose refers to the amount of energy released when glucose is metabolized. In this context, glucose provides approximately 4 kilocalories (Cal) per gram. Understanding this concept is crucial for converting the daily caloric needs of the population into a mass of glucose, as it directly links the energy requirements to the amount of glucose needed.
Recommended video:
Guided course
01:56
Gas Constant Values

Thermochemical Equations

Thermochemical equations provide information about the heat changes associated with chemical reactions. The equation given indicates that the combustion of glucose releases 2803 kJ of energy per mole. This concept is important for calculating the total energy required for the global population and subsequently determining the mass of glucose needed to provide that energy over a year.
Recommended video:
Guided course
01:13
Thermochemical Equations
Related Practice
Textbook Question

The heat of combustion of ethanol, C2H5OH(l), is -1367 kJ/mol. A batch of Sauvignon Blanc wine contains 10.6% ethanol by mass. Assuming the density of the wine to be 1.0 g/mL, what is the caloric content due to the alcohol (ethanol) in a 6-oz glass of wine (177 mL)?

3
views
Textbook Question

The standard enthalpies of formation of gaseous propyne (C3H4), propylene (C3H6), and propane (C3H8) are +185.4, +20.4, and -103.8 kJ/mol, respectively. (b) Calculate the heat evolved on combustion of 1 kg of each substance.

597
views
Textbook Question

The standard enthalpies of formation of gaseous propyne (C3H4), propylene (C3H6), and propane (C3H8) are +185.4, +20.4, and -103.8 kJ/mol, respectively. (c) Which is the most efficient fuel in terms of heat evolved per unit mass?

1934
views
Textbook Question

The automobile fuel called E85 consists of 85% ethanol and 15% gasoline. E85 can be used in the so-called flex-fuel vehicles (FFVs), which can use gasoline, ethanol, or a mix as fuels. Assume that gasoline consists of a mixture of octanes (different isomers of C8H18), that the average heat of combustion of C8H18(l) is 5400 kJ/mol, and that gasoline has an average density of 0.70 g/mL. The density of ethanol is 0.79 g/mL. (a) By using the information given as well as data in Appendix C, compare the energy produced by combustion of 1.0 L of gasoline and of 1.0 L of ethanol.

1969
views
Textbook Question

Two positively charged spheres, each with a charge of 2.0⨉10-5 C, a mass of 1.0 kg, and separated by a distance of 1.0 cm, are held in place on a frictionless track. (a) What is the electrostatic potential energy of this system?

1116
views
Textbook Question

The air bags that provide protection in automobiles in the event of an accident expand because of a rapid chemical reaction. From the viewpoint of the chemical reactants as the system, what do you expect for the signs of q and w in this process?

885
views