Calorimetry Lab
Mix hot and cold substances and watch their temperatures converge over time. Adjust masses, specific heats, and heat loss to explore how calorimeters work and verify conservation of energy through heat exchange.
Guided Experiment: Heat Exchange Between Water Samples
If you mix 100 g of water at 80°C with 100 g of water at 20°C in a coffee cup calorimeter, what will the equilibrium temperature be? What if one sample has twice the mass?
Write your hypothesis in the Lab Report panel, then click Next.
Controls
Results
Temperature vs Time
Data Table
(0 rows)| # | Trial | Time(s) | T hot(°C) | T cold(°C) | T equilibrium(°C) | q(J) |
|---|
Reference Guide
Heat Transfer Equation
The heat absorbed or released by a substance depends on its mass, specific heat, and temperature change.
Where q is heat in joules, m is mass in grams, c is specific heat in J/(g·°C), and deltaT is the temperature change. A positive q means heat absorbed; negative means heat released.
Conservation of energy: heat released by the hot sample equals heat absorbed by the cold sample in an ideal calorimeter.
Calorimeter Types
Coffee cup calorimeter — a simple insulated cup open to the atmosphere. Used for reactions in solution. Heat loss to surroundings can affect measurements.
Bomb calorimeter — a sealed, rigid steel container submerged in water. Used for combustion reactions. Constant volume, minimal heat loss, more accurate.
The key difference is heat loss rate: bomb calorimeters are much better insulated, so the observed equilibrium temperature is closer to the theoretical value.
Specific Heat
Specific heat c is the energy needed to raise 1 gram of a substance by 1°C. Water has one of the highest specific heats of any common material.
Materials with high specific heat resist temperature change. This is why water is used as a coolant and why coastal regions have milder climates than inland areas.
| Material | c (J/g·°C) |
|---|---|
| Water | 4.184 |
| Aluminum | 0.897 |
| Copper | 0.385 |
| Iron | 0.449 |
| Lead | 0.128 |
Conservation of Energy
Temperature approaches equilibrium exponentially, following Newton's law of cooling.
Where k is the rate constant that depends on thermal contact and heat capacities. Larger total heat capacity means slower equilibration (smaller k). Heat loss to the environment adds a further decay term, lowering the observed final temperature below the ideal T_eq.
You can determine the specific heat of an unknown substance by measuring the observed T_eq and rearranging the heat balance equation.