Molar Volume of a Gas at STP

Experimentally determining 22.4 L/mol using butane

Gas Laws Intermediate (High School) 35 min ~$6.00

Objective

Determine the molar volume of butane gas at STP by measuring the mass and volume of gas released from a lighter.

Background

A butane lighter releases pure C₄H₁₀ gas. By weighing the lighter before and after releasing gas into a water-displacement collection system, and measuring the volume collected, the molar volume can be calculated and compared to the theoretical 22.4 L/mol at STP.

Safety Warnings

  • Butane is extremely flammable — NO open flames during the experiment
  • Ensure adequate ventilation
  • Do not inhale butane

Required PPE

goggles

Materials

  • Butane lighter (1)
    Disposable, transparent preferred
  • Distilled water (1 L)
  • Ice (as needed)
    Optional, for STP correction

Equipment

Pneumatic trough or large container Graduated cylinder (500 mL or 1 L) Analytical balance (0.01 g) Thermometer Barometer Rubber tubing

Procedure

1

Weigh the butane lighter on the analytical balance. Record the mass to 0.01 g.

2 min
2

Fill the graduated cylinder with water, invert it in the pneumatic trough.

3 min
3

Connect rubber tubing to the lighter nozzle. Submerge the other end under the graduated cylinder.

3 min No flames nearby
4

Release butane slowly into the inverted cylinder, collecting 200-400 mL of gas.

5 min Butane is flammable
5

Record the volume of gas collected. Equalize water levels first.

2 min
6

Reweigh the lighter. The mass difference is the mass of butane released.

2 min
7

Record temperature and pressure. Calculate moles of butane (M=58.12 g/mol). Correct volume to STP using combined gas law.

8 min
8

Calculate molar volume = V(STP)/n. Compare with theoretical 22.4 L/mol.

5 min

Expected Results

0.3 g butane = 0.00516 mol should occupy about 116 mL at STP. Molar volume should be approximately 22-24 L/mol, within 5-10% of the theoretical 22.4 L/mol.

Cleanup

Ensure no butane remains in the room — ventilate well. Drain water apparatus. Store lighter safely.

Details

Category
Gas Laws
Difficulty
Intermediate (High School)
Duration
35 min
Est. Cost
$6.00
Steps
8
Materials
3

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Frequently Asked Questions

What is the objective of Molar Volume of a Gas at STP?
Determine the molar volume of butane gas at STP by measuring the mass and volume of gas released from a lighter.
How difficult is Molar Volume of a Gas at STP?
This experiment is rated as Intermediate (High School). It takes approximately 35 minutes to complete.
What safety precautions are needed for Molar Volume of a Gas at STP?
Key safety precautions include: Butane is extremely flammable — NO open flames during the experiment; Ensure adequate ventilation; Do not inhale butane.
What materials are needed for Molar Volume of a Gas at STP?
The main materials required are: Butane lighter, Distilled water, Ice.
What results should I expect from Molar Volume of a Gas at STP?
0.3 g butane = 0.00516 mol should occupy about 116 mL at STP. Molar volume should be approximately 22-24 L/mol, within 5-10% of the theoretical 22.4 L/mol.