Textbook Question
(a) A serving of a particular ready-to-serve chicken noodle soup contains 2.5 g fat, 14 g carbohydrate, and 7 g protein. Estimate the number of Calories in a serving.
Ch.5 - Thermochemistry
Chapter 5, Problem 96
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)?
Verified step by step guidance1
Convert the volume of wine from mL to grams using the density: \( \text{mass} = \text{volume} \times \text{density} \).
Calculate the mass of ethanol in the wine using the percentage by mass: \( \text{mass of ethanol} = \text{total mass of wine} \times \frac{10.6}{100} \).
Convert the mass of ethanol to moles using the molar mass of ethanol \( C_2H_5OH \), which is approximately 46.08 g/mol: \( \text{moles of ethanol} = \frac{\text{mass of ethanol}}{\text{molar mass of ethanol}} \).
Calculate the total heat of combustion for the ethanol 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.
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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, this value is -1367 kJ/mol, indicating that this amount of energy is released per mole of ethanol burned. Understanding this concept is crucial for calculating the energy content of ethanol in wine.
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Combustion Apparatus
Mass Percent Concentration
Mass percent concentration refers to the mass of a solute divided by the total mass of the solution, expressed as a percentage. In this case, the wine contains 10.6% ethanol by mass, meaning that in 100 grams of wine, there are 10.6 grams of ethanol. This concept is essential for determining the amount of ethanol in a specific volume of wine.
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Density and Volume Conversion
Density is defined as mass per unit volume, and it allows for the conversion between mass and volume. Given that the density of the wine is 1.0 g/mL, this means that 1 mL of wine has a mass of 1 gram. This concept is important for converting the volume of wine (177 mL) into mass, which is necessary for calculating the caloric content from the ethanol present.
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Related Practice
Textbook Question
The heat of combustion of fructose, C6H12O6, is -2812 kJ/mol. If a fresh golden delicious apple weighing 4.23 oz (120 g) contains 16.0 g of fructose, what caloric content does the fructose contribute to the apple?
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. (a) Calculate the heat evolved per mole on combustion of each substance to yield CO2(g) and H2O(g). (b) Calculate the heat evolved on combustion of 1 kg of each substance.
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?
Textbook Question
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(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