Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 5: Problem 89

(a) What is meant by the term fuel value? (b) Which is a greater source of energy as food, 5 g of fat or 9 g of carbohydrate? (c) The metabolism of glucose produces \(\mathrm{CO}_{2}(g)\) and \(\mathrm{H}_{2} \mathrm{O}(l) .\) How does the human body expel these reaction products?

Short Answer

Expert verified
(a) Fuel value refers to the amount of energy released when a specific quantity of a substance is completely combusted or metabolized, measured in calories, kilocalories, or Joules per gram. (b) 5g of fat provides 45 kcal (188.5 kJ) of energy, while 9g of carbohydrate provides 36 kcal (150.3 kJ); therefore, 5g of fat is a greater source of energy than 9g of carbohydrate. (c) The human body expels carbon dioxide (CO₂) through the respiratory system, specifically during exhalation, and water (H₂O) through various means such as perspiration, urine, and exhaled air.

Step by step solution

01

(a) Definition of Fuel Value

Fuel value refers to the amount of energy that is released when a specific quantity of a substance is completely combusted or metabolized. It is usually measured in calories, kilocalories, or Joules per gram.
02

(b) Comparison of Energy Content of Fat and Carbohydrate

To compare the energy content of 5g of fat and 9g of carbohydrate, we need to know the energy content per gram of fat and carbohydrate: - Fat contains about 9 calories (or 37.7 kilojoules) per gram. - Carbohydrate contains about 4 calories (or 16.7 kilojoules) per gram. Now, let's calculate how much energy 5g of fat and 9g of carbohydrate provide: - Energy from 5g of fat: 5g x 9 kcal/g = 45 kcal (188.5 kJ) - Energy from 9g of carbohydrate: 9g x 4 kcal/g = 36 kcal (150.3 kJ)
03

(b) Conclusion

Since 45 kcal (from 5g of fat) is greater than 36 kcal (from 9g of carbohydrate), 5g of fat is a greater source of energy than 9g of carbohydrate.
04

(c) Expulsion of Carbon Dioxide and Water from Human Body

During the metabolism of glucose in the human body, carbon dioxide (CO₂) and water (H₂O) are produced as reaction products. The human body expels these products in the following ways: - Carbon dioxide (CO₂) is expelled through the respiratory system, specifically during exhalation. It is transported from the cells to the lungs via the bloodstream, where it is exchanged for oxygen, and then exhaled through the mouth and nose. - Water (H₂O) is expelled from the body through various means including perspiration (sweat), urine, and exhaled air. The kidneys play a crucial role in regulating the amount of water expelled from the body.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

(a) When a 0.235 -g sample of benzoic acid is combusted in a bomb calorimeter (Figure 5.19\()\) , the temperature rises \(1.642^{\circ} \mathrm{C} .\) When a \(0.265-\mathrm{g}\) sample of caffeine, \(\mathrm{C}_{8} \mathrm{H}_{10} \mathrm{N}_{4} \mathrm{O}_{2}\) is burned, the temperature rises \(1.525^{\circ} \mathrm{C} .\) Using the value 26.38 \(\mathrm{kJ} / \mathrm{g}\) for the heat of combustion of benzoic acid, calculate the heat of combustion per mole of caffeine at constant volume. (b) Assuming that there is an uncertainty of \(0.002^{\circ} \mathrm{C}\) in each temperature reading and that the masses of samples are measured to \(0.001 \mathrm{g},\) what is the estimated uncertainty in the value calculated for the heat of combustion per mole of caffeine?

A 1.800 -g sample of phenol \(\left(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{OH}\right)\) was burned in a bomb calorimeter whose total heat capacity is 11.66 \(\mathrm{kJ} /^{\circ} \mathrm{C}\) The temperature of the calorimeter plus contents increased from 21.36 to \(26.37^{\circ} \mathrm{C}\) (a) Write a balanced chemical equation for the bomb calorimeter reaction. (b) What is the heat of combustion per gram of phenol? Per mole of phenol?

Under constant-volume conditions, the heat of combustion of glucose \(\left(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\right)\) is 15.57 \(\mathrm{kJ} / \mathrm{g}\) . A 3.500 -g sample of glucose is burned in a bomb calorimeter. The temperature of the calorimeter increases from 20.94 to \(24.72^{\circ} \mathrm{C}\) (a) What is the total heat capacity of the calorimeter? (b) If the size of the glucose sample had been exactly twice as large, what would the temperature change of the calorimeter have been?

The Sun supplies about 1.0 kilowatt of energy for each square meter of surface area \(\left(1.0 \mathrm{kW} / \mathrm{m}^{2},\) where a watt \(=1 \mathrm{J} / \mathrm{s}\right)\) Plants produce the equivalent of about 0.20 \(\mathrm{g}\) of sucrose \(\left(\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}\right)\) per hour per square meter. Assuming that the sucrose is produced as follows, calculate the percentage of sunlight used to produce sucrose. $$\begin{array}{c}{12 \mathrm{CO}_{2}(g)+11 \mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}+12 \mathrm{O}_{2}(g)} \\ \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad \quad {\Delta H=5645 \mathrm{kJ}}\end{array}$$

Calculate \(\Delta E\) and determine whether the process is endothermic or exothermic for the following cases: (a) \(q=0.763 \mathrm{kJ}\) and \(w=-840 \mathrm{J} .\) (b) A system releases 66.1 \(\mathrm{kJ}\) of heat to its surroundings while the surroundings do 44.0 \(\mathrm{kJ}\) of work on the system.
See all solutions

Recommended explanations on Chemistry Textbooks

Chemical Reactions

Read Explanation

Organic Chemistry

Read Explanation

Making Measurements

Read Explanation

Chemistry Branches

Read Explanation

Ionic and Molecular Compounds

Read Explanation

Physical Chemistry

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free