Domestic LPG is stored and delivered in cylinders as a liquid. Estimate the density of liquid LPG relative to water (1 g/cc): is it about one fourth, one third, half, or one eighth that of water?

Introduction / Context:
Liquefied petroleum gas (LPG) in household cylinders exists largely as liquid under pressure. Knowing its density relative to water helps in safe handling, storage design, and fill calculations.

Given Data / Assumptions:

• Water density ≈ 1 g/cc at ambient conditions.
• LPG composition: mixtures of propane and butane.
• Question seeks an approximate fraction of water density.

Concept / Approach:
Typical liquid-phase densities: propane ≈ 0.50–0.52 g/cc (ambient), butane ≈ 0.57–0.60 g/cc. Commercial LPG blends fall near the middle of this range depending on season and locale, roughly about half the density of water.

Step-by-Step Solution:

Verification / Alternative check:
Cylinder mass/volume calculations used by distributors align with ~0.5–0.55 g/cc, validating the “half” estimate.

Why Other Options Are Wrong:

Common Pitfalls:
Confusing LPG vapour density with liquid density; vapour density is relative to air, not water.

Final Answer:
Half