Calorimetry Virtual Experiment Lab
A full-workflow chemistry investigation. Choose an investigation, state your hypothesis, identify the independent and dependent variables, collect replicated trials, fit a regression line, and derive specific heat, the calorimeter constant, or the enthalpy of combustion with quantified uncertainty.
Choose an Investigation
Investigation A. Specific Heat of an Unknown Metal
How does the temperature drop of a heated metal compare to the temperature rise of the water it is dropped into, and what does the ratio tell us about the metal's specific heat?
Initial sample temperature T_sample (vary from 60 °C to 100 °C)
Final equilibrium temperature T_f of the water + sample mixture
- Sample mass (constant)
- Water mass and initial temperature (constant)
- Calorimeter constant C_cal (assumed calibrated)
- Atmospheric pressure (open coffee-cup)
Predict how the difference (T_sample − T_f) compares to (T_f − T_water). What single property of the metal does that ratio reveal?
Plotting (T_sample − T_f) on y and (T_f − T_water) on x yields a straight line through the origin. Slope = (m_water·c_water + C_cal) / (m_sample·c_sample), so c_sample = (m_water·c_water + C_cal) / (m_sample·slope). Copper sits near 0.385 J/(g·°C), aluminum near 0.897 J/(g·°C).
- Heat the same metal sample to 60, 70, 80, 90, and 100 °C in turn
- Drop each into a fresh water bath at the same starting temperature
- Measure T_f and tabulate (T_sample − T_f) and (T_f − T_water)
- Fit a straight line and read the slope
- Compute c_sample from the slope and compare with the accepted value
Setup
Each "Record Trial" applies realistic measurement noise of ±0.2 °C on the thermometer and ±0.05 g on the balance, then appends the trial to the data table.
Current Setup
T_sample − T_f (°C) vs T_f − T_water (°C)
Record at least 2 trials (or load sample data) to see the plot.
Regression & Error Analysis
Record at least 2 trials to compute the regression. For a defensible fit you should collect 6 or more trials across the full range of the IV.
Data Table
(0 rows)| # | Trial | Sample m(g) | T sample(°C) | Water m(g) | T water(°C) | T final(°C) | T_s − T_f(°C) | T_f − T_w(°C) | c_sample (trial)(J/(g·°C)) |
|---|
Reference Guide
Investigation Workflow
Every credible calorimetry result comes from more than a single measurement. It comes from a hypothesis, clearly identified variables, replicated trials, a fit line, and an honest error analysis.
- State a testable hypothesis
- Identify IV, DV, and controlled variables
- Record at least 6 replicated trials across the range of the IV
- Fit a regression line and inspect residuals
- Quote a final value with uncertainty and percent error
Energy Balance
The first law of thermodynamics says heat lost by the hot side equals heat gained by the cold side and by the calorimeter itself:
Solving for the equilibrium temperature gives:
With c_water = 4.184 J/(g·°C), measuring T_f lets you solve for any single unknown in the balance.
Coffee-Cup vs Bomb Calorimetry
Coffee-cup calorimetry. Open to the atmosphere at constant pressure. Measures q_p, which equals ΔH for the reaction. Used for specific heat, heats of solution, and heats of neutralization.
Bomb calorimetry. Sealed rigid bomb at constant volume. Measures q_v, which equals ΔU. For most combustion reactions ΔH is close to ΔU because the Δn_gas term is small.
The slope of q versus fuel mass times molar mass gives the molar enthalpy.
Error Analysis
Report each derived value with uncertainty and percent error.
Slope uncertainty propagates to derived quantities via the relative-error rule δX/X = δslope/slope. Largest contributors are thermometer resolution (±0.1 to 0.2 °C), heat loss to the surroundings during sample transfer, and incomplete combustion in bomb runs.
