The Calorimeter Caper

The Calorimeter Caper A Digital Forensic Investigation Using Specific Heat Capacity Case Brief “A thief broke into the chemistry storage room using a heated metal rod. Four suspects were in the building that night, each assigned to a different metal: ● Sam - aluminum ● Sal - copper ● Saul - iron/steel ● Sally - lead. The culprits left 2 metal samples behind. You are the forensic chemistry team. Your mission: identify the unknown metal and solve the crime.” Learning Goals ● Apply conservation of energy in calorimetry. ● Calculate the specific heat capacity of an unknown metal. ● Compare results to a forensic reference database. ● Use evidence to identify a suspect. Pre-Activity Warm-Up Write the questions and answers in your lab book on page*** 1. What is specific heat capacity? 2. Which object cools faster: one with a high 𝑐 or low? 3. What law of energy transfer allows us to calculate the unknown identity? Show the work for your following calculation in your notebook Unknown Metal A – Trial 1 Mass of water: 100.0 g Mass of metal: 52.0 g Initial water temp: 22.0 °C Initial metal temp: 99.0 °C Final temp: 28.4 °C Unknown Metal B – Trial 1 Mass of water: 101.0 g Mass of metal: 45.5 g Initial water temp: 21.8 °C Initial metal temp: 99.0 °C Final temp: 23.7 °C The Lab Messed Up…. The crime lab’s reference table of metal specific heat capacities was lost Luckily, we still have lab notes from past experiments. Your job: use calorimetry data to recalculate the specific heat capacities of the metals. Once you solve all 4, you’ll have rebuilt the lost database. Aluminum A 50.0 g piece of aluminum was heated to 100.0 °C and dropped into 100.0 g of water at 20.0 °C. The final temperature of the system was 27.0 °C. 👉 What is the specific heat capacity of aluminum? Copper A 75.0 g sample of copper at 95.0 °C was placed in 100.0 g of water at 25.0 °C. Final temperature: 29.0 °C. 👉 What is the specific heat capacity of copper? Iron/Steel A 60.0 g sample of iron was heated to 120.0 °C and placed in 120.0 g of water at 22.0 °C. Final temperature: 26.0 °C. 👉 What is the specific heat capacity of iron? Lead A 40.0 g piece of lead at 100.0 ° C was placed in 100.0 g of water at 20.0 °C. Final temperature: 21.4 °C. 👉 What is the specific heat capacity of lead? Who did it? Compare your crime scene samples to your calculated knowns. Activity Post Activity Write the questions and answers in your lab book on page*** 1. What was your calculated specific heat? 2. Which suspect did you identify? 3. Calculate percent error compared to the reference value. 4. List two sources of error in your calculations. 5. If two metals had similar heat capacities, what other property could you test?