At atmospheric pressure (14.7 psia), ammonia boils at?

At atmospheric pressure (14.7 psia), ammonia boils at?

• A. 0 F
• B. -28 F
• C. 32 F
• D. -100 F

Answer: (A)

Boiling point is the temperature at which a liquid’s vapor pressure equals the surrounding pressure. At atmospheric pressure (14.7 psia), ammonia’s normal boiling point is about -33°C, which is roughly -28°F. So, at 1 atm, ammonia begins to boil around -28°F: below that temperature it would be a liquid, and above it it tends to be a gas. The other temperatures are not the equilibrium point for 1 atm: 0°F is warmer than the boiling point, so ammonia would be a gas at that pressure, and the same idea applies to the other options.

Boiling point is the temperature at which a liquid’s vapor pressure equals the surrounding pressure. At atmospheric pressure (14.7 psia), ammonia’s normal boiling point is about -33°C, which is roughly -28°F. So, at 1 atm, ammonia begins to boil around -28°F: below that temperature it would be a liquid, and above it it tends to be a gas. The other temperatures are not the equilibrium point for 1 atm: 0°F is warmer than the boiling point, so ammonia would be a gas at that pressure, and the same idea applies to the other options.