Calorimetry Problems and Solutions Summary

Problem 8.2.1: Heat Loss in Water Bottles

• Scenario: Two water bottles (500 mL and 2 L) are cooled in a refrigerator.
• Student Opinions:
  • Student A: Both bottles lost the same heat (Incorrect).
  • Student B: 2 L bottle lost more heat (Correct).
  • Student C: 500 mL bottle lost more heat because it cooled faster (Incorrect).
  • Student D: Cannot determine without initial and final temperatures (Incorrect).
• Correct Explanation: The 2 L bottle lost more heat due to greater mass, demonstrated by the formula q = cmΔT.

Problem 8.2.2: Mixing Water and Coffee

• Objective: Find how much water at 23°C must be added to 180 mL of coffee at 95°C to reach 60°C.
• Answer: 170 mL of water.

Problem 8.2.3: Temperature Reduction by Spoon

• Scenario: A silver spoon is placed in a cup of coffee.
• Objective: Determine temperature drop of the coffee.
• Answer: Temperature drops by 1°C.

Problem 8.2.4: Aluminum Spoon and Coffee Temperature

• Scenario: An aluminum spoon is placed in coffee.
• Objective: Determine final equal temperature and identify mistakes in previous calculations.
• Answers:
  • Final Temperature: 81.95°C
  • Error Explanation: Found incorrect temperature (88°C) exceeds initial coffee temperature.

Problem 8.2.5: Heat Transfer in Car Engine

• Objective: Calculate heat transferred by 1 gallon of water cooling from 240°F to 175°F.
• Answer: 5.7102 kJ.

Problem 8.2.6: Reaction of NaCl and AgNO3

• Scenario: NaCl and AgNO3 reaction in a calorimeter.
• Objective: Calculate heat produced.
• Answer: 693 J.

Problem 8.2.7: Temperature Drop in Calorimeter Reaction

• Scenario: Reaction between Ba(OH)2·8H2O and NH4SCN.
• Objective: Calculate heat absorbed due to temperature drop.
• Answer: 1.4 kJ.

Problem 8.2.8: Fructose Combustion

• Scenario: Combustion of 1 g fructose in a bomb calorimeter.
• Objective: Determine heat (q) for the reaction.
• Answer: 15.64 kJ.

Problem 8.2.9: Coal Combustion for Electricity

• Scenario: Coal burned in a bomb calorimeter to determine heat of combustion per ton.
• Objective: Calculate heat produced per ton of coal.
• Answer: 2.91 x 10^7 kJ.

Problem 8.2.10: Sucrose Caloric Content

• Objective: Determine mass of sucrose in a teaspoon worth 16 Calories.
• Answer: 3.9 g.

Problem 8.2.11: Carbohydrate Mass in Diet Soda

• Objective: Determine maximum carbohydrate mass in a serving containing less than 1 Calorie.
• Answer: 0.24 g.

Problem 8.2.12: Fat Mass in Ice Cream

• Scenario: Calculate mass of fat from caloric content in ice cream.
• Objective: Find mass of fat stored for 1100 Calories.
• Answer: 120.87 g (or 0.266 lbs).

Problem 8.2.13: Caloric Content of Cereal

• Scenario: Analyze a serving of cereal based on its macronutrient composition.
• Objective: Calculate total Calorie content.
• Answer: 140 Calories.

Contributors:

• Paul Flowers, Klaus Theopold, Richard Langley
• Adelaide Clark
• Licensed under Creative Commons Attribution License 4.0