Textbook Question
(a) A serving of a particular ready-to-serve brown & wild rice meal contains 4.5 g fat, 42 g carbohydrate, and 4.0 g protein. Estimate the number of calories in a serving.
395
views
Ch.5 - Thermochemistry
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232
Not the one you use?Change textbookSelect a different textbook
Table of contents
- Ch.1 - Introduction: Matter, Energy, and Measurement140
- Ch.2 - Atoms, Molecules, and Ions192
- Ch.3 - Chemical Reactions and Reaction Stoichiometry172
- Ch.4 - Reactions in Aqueous Solution156
- Ch.5 - Thermochemistry151
- Ch.6 - Electronic Structure of Atoms137
- Ch.7 - Periodic Properties of the Elements127
- Ch.8 - Basic Concepts of Chemical Bonding143
- Ch.9 - Molecular Geometry and Bonding Theories167
- Ch.10 - Gases147
- Ch.11 - Liquids and Intermolecular Forces97
- Ch.12 - Solids and Modern Materials129
- Ch.13 - Properties of Solutions126
- Ch.14 - Chemical Kinetics175
- Ch.15 - Chemical Equilibrium107
- Ch.16 - Acid-Base Equilibria127
- Ch.17 - Additional Aspects of Aqueous Equilibria133
- Ch.18 - Chemistry of the Environment88
- Ch.19 - Chemical Thermodynamics140
- Ch.20 - Electrochemistry137
- Ch.21 - Nuclear Chemistry99
- Ch.22 - Chemistry of the Nonmetals66
- Ch.23 - Transition Metals and Coordination Chemistry69
- Ch.24 - The Chemistry of Life: Organic and Biological Chemistry11
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232Not the one you use?Change textbook
Chapter 5, Problem 94
The heat of combustion of ethanol, C2H5OH(l), is -1367 kJ/mol. A bottle of stout (dark beer) contains up to 6.0% ethanol by mass. Assuming the density of the beer to be 1.0 g/mL, what is the caloric content due to the alcohol (ethanol) in a bottle of beer (500 mL)?
Verified step by step guidance1
Calculate the mass of the beer using its volume and density: \( \text{mass} = \text{volume} \times \text{density} \).
Determine the mass of ethanol in the beer using the percentage by mass: \( \text{mass of ethanol} = \text{mass of beer} \times \frac{6.0}{100} \).
Convert the mass of ethanol to moles using the molar mass of ethanol (C\(_2\)H\(_5\)OH), which is approximately 46.08 g/mol: \( \text{moles of ethanol} = \frac{\text{mass of ethanol}}{46.08} \).
Calculate the total heat of combustion for the ethanol in the beer using the heat of combustion per mole: \( \text{total heat} = \text{moles of ethanol} \times (-1367 \text{ kJ/mol}) \).
Convert the total heat from kJ to calories, knowing that 1 kJ = 239.006 calories.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Heat of Combustion
The heat of combustion is the amount of energy released when a substance undergoes complete combustion with oxygen. For ethanol, the heat of combustion is -1367 kJ/mol, indicating that this amount of energy is released per mole of ethanol burned. This concept is crucial for calculating the energy content of ethanol in the beer.
Recommended video:
Guided course
02:24
Combustion Apparatus
Mass Percent Concentration
Mass percent concentration is a way to express the concentration of a component in a mixture, calculated as the mass of the component divided by the total mass of the mixture, multiplied by 100. In this case, the beer contains 6.0% ethanol by mass, which means that in 100 g of beer, there are 6 g of ethanol. This concept is essential for determining the total mass of ethanol in the 500 mL of beer.
Density and Volume Relationship
Density is defined as mass per unit volume, and it allows us to convert between the volume of a liquid and its mass. Given that the density of the beer is 1.0 g/mL, a 500 mL bottle of beer has a mass of 500 g. Understanding this relationship is vital for calculating the total mass of ethanol present in the beer based on its volume.
Recommended video:
Guided course
01:09Relationship of Volume and Moles Example
Related Practice
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?
1938
views
Textbook Question
It is interesting to compare the 'fuel value' of a hydrocarbon in a hypothetical world where oxygen is not the combustion agent. The enthalpy of formation of CF4(g) is -679.9 kJ/mol. Which of the following two reactions is the more exothermic?
CH4(g) + 2 O2(g) β CO2(g) + 2 H2O(g)
CH4(g) + 4 F2(g) β CF4(g) + 4 HF(g)
854
views
Textbook Question
The heat of combustion of fructose, C6H12O6, is -2812 kJ/mol. If a fresh golden delicious apple weighing 120 g contains 16.0 g of fructose, what caloric content does the fructose contribute to the apple?
1493
views
Textbook Question
At the end of 2012, global population was about 7.0 billion people. 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(π) and H2O(π) according to the following thermochemical equation: C6H12O6(s) + 6 O2(π) β 6 CO2(π) + 6 H2O(π) ΞHΒ° = -2803 kJ
839
views