Chapter 17 Part 4

Solid-Vapor Equilibrium Sublimation is a process in which molecules go directly from the solid into the vapor phase (deposition is the reverse process).

Sublimation Iodine and dry ice are substances that commonly undergo sublimation. Which of these can reach equilibrium?

Deposition The formation of frost.

Boiling A substance boils when the vapor pressure of the liquid is equal to the atmospheric pressure.A substance boils when the vapor pressure of the liquid is equal to the atmospheric pressure.

How could I boil this water?A A

What is temperature of the water?A A

Why does water boil at 100°C?

Is there another way to boil the water?

What is the pressure inside the bell jar if the water is boiling at 20°C?

We can make water boil at “any” temperature.

234 Elevation = 29,035 ft.

Volcanic Vents

LONDON — Scientists using a remote-controlled submarine have discovered the deepest known volcanic vent and say the superheated waters inside could contain undiscovered marine species and perhaps even clues to the origin of life on earth. Experts aboard the RRS James Cook said they found the underwater volcanic vent more than three miles (five kilometers) beneath the surface of the Caribbean. Volcanic vents are areas where sea water seeps into small cracks that penetrate deep into the earth's crust — some reaching down more than a mile (two kilometers.) Temperatures there can reach 750 degrees Fahrenheit (400 degrees Celsius), heating the water to the point where it can melt lead. The blazing hot mineral-rich fluid is expelled into the icy cold of the deep ocean, creating a smoke-like effect and leaving behind towering chimneys of metal ore, some two stories tall. The spectacular pressure — 500 times stronger than the earth's atmosphere — keeps the water from boiling.

Which beaker of water has had more heat added to it? Boiling for 5 minutes Boiling for 30 minutes

Which beaker of water is hotter? Boiling for 5 minutes Boiling for 30 minutes

What would happen to this water as it boiled? It gets colder

How can we continue to boil the water as it cools?

What happens when the vapor pressure of water reaches 4.6 mm Hg.

What is the boiling point of ethanol at normal air pressure?

What is the boiling point of water at an air pressure of 400 torr? ≈82°C

At what air pressure will Diethyl ether boil at 20°C? ≈450 torr

How do these substances compare in terms of Van der Waals forces, rate of evaporation, vapor pressure, and volatility ?

Diethyl ether has the least Van der Waals forces, and the greatest rate of evaporation, vapor pressure, and volatility.

“Which would you expect to have the higher boiling point?

He = -269˚C Rn = -62˚C

Homework  Worksheet 2 Chapter 17