Physics and Gas Laws Flashcards

A diver at 66 feet (20 m) breathes from a tank with 3000 psi. Using Boyle's Law, approximately how much air (in surface-equivalent volume) has been consumed if the tank now reads 1500 psi?

Answer: Half the tank's surface-equivalent volume

Pressure drop from 3000 to 1500 psi means half the tank's compressed air is gone, regardless of depth.

Charles's Law states that at constant pressure, the volume of a gas is proportional to its:

Answer: Absolute temperature

Charles's Law relates gas volume directly to absolute temperature (Kelvin) at constant pressure.

A scuba cylinder is filled to 3000 psi at 70°F (21°C). If the cylinder cools to 30°F (-1°C), what happens to the pressure inside?

Answer: It decreases

By Gay-Lussac's Law, pressure decreases as temperature drops at constant volume.

Which law explains why a diver's lungs could rupture if they hold their breath while ascending?

Answer: Boyle's Law

Boyle's Law shows that as pressure decreases on ascent, gas volume expands — holding breath traps that expanding gas in the lungs.

According to Dalton's Law, the partial pressure of oxygen in air at 3 ATA is:

Answer: 0.63 ATA

Oxygen is 21% of air, so at 3 ATA: 0.21 × 3 = 0.63 ATA partial pressure.

Henry's Law is most directly related to which diving concern?

Answer: Decompression sickness

Henry's Law states that gas dissolves into liquid proportional to its partial pressure — the principle behind nitrogen absorption and DCS.

A diver descends to 99 feet (30 m). The absolute pressure in ATA is:

Answer: 4 ATA

Every 33 feet of seawater adds 1 ATA; 99 ft = 3 ATA of water pressure + 1 ATA atmosphere = 4 ATA.