Question

use a graduated cylinder to add approximately 40 mL of water to the calorimeter. Measure the mass of the calorimeter (no lid) and water to the nearest 0.01 g.

Answer 1

Step-by-step procedure and tips

1. Prepare equipment
- Make sure the calorimeter (no lid) is clean and dry.
- Use an analytical balance or top-loading balance that reads to 0.01 g. Ensure the balance is on a level, draft-free surface and warmed up/stabilized.

2. Measure empty calorimeter mass
- Place the empty calorimeter on the balance. Wait for the reading to stabilize and record the mass to the nearest 0.01 g (e.g., 123.45 g). Label this value M_empty.

3. Add ≈40 mL water
- Use a clean graduated cylinder. Pour water into the cylinder a bit above the 40.0 mL mark and adjust down to the meniscus so the bottom of the meniscus sits at 40.0 mL at eye level.
- Slowly pour the 40 mL into the calorimeter. If you need more accuracy, you can add slightly less and then use a transfer pipette or dropper to reach the desired volume.

4. Measure calorimeter + water mass
- Wipe any droplets off the outside/bottom of the calorimeter (but do not dry the interior). Place the calorimeter with water on the balance, wait for the reading to stabilize, and record the mass to the nearest 0.01 g. Label this M_full.

5. Calculate mass of water
- Mass of water = M_full − M_empty. Record with units (g).

Additional tips and cautions
- If you prefer, you may weigh the empty calorimeter, tare the balance to zero with the empty calorimeter on it, and then carefully add the water while the calorimeter stays on the balance; this gives the mass of added water directly, but adding liquid on the balance risks spills—be careful.
- Avoid drafts and vibrations while weighing. Wait for the balance to show a stable digit (often indicated by a stability icon).
- Don’t let water contact the balance pan—use a tray under the calorimeter if needed.
- Record all values, including the balance ID and room temperature if required by your lab procedure.