Specific heat capacity measures thermal inertia

Steps:

• Define specific heat capacity as energy (J) needed to raise 1 g of substance by 1°C.
• Compare given values: air (1.0 J/g°C) requires less energy than liquid water (4.3 J/g°C) or steam (2.1 J/g°C).
• Recall hydrogen gas specific heat is ~7.15 J/g°C (from molar heat capacity 14.3 J/mol°C divided by 2 g/mol).
• Conclude B is true since 7.15 > 4.3, needing more energy for hydrogen than water.

Why B is correct:

• By definition, higher specific heat (c = Q / (m ΔT)) means more heat Q for same mass m and ΔT, and hydrogen's c exceeds water's.

Why the others are wrong:

• A: Air's low c (1.0) makes it less resistant to temperature changes than water's high c (4.3).
• C: Specific heat applies to temperature rise, not phase change like vaporization (latent heat).
• D: Gas phase (steam) has fewer hydrogen bonds than liquid water, explaining lower c for steam.

Final answer: B