Phase Diagrams

Water exists as a _____________ at 3 mmHg and 50 °C.

• solid
• liquid
• gas
• supercritical fluid

Water exists as a _____________ at 700 mmHg and 50 °C.

• solid
• liquid
• gas
• supercritical fluid

Tags

NGSS.HS-ESS2-5

What phase change(s) may occur at pressures below 4.58 mmHg?

• sublimation/deposition
• melting/freezing
• all phase changes are possible at these pressures
• vaporization/condensation

The pressure is increased on a sample of water at 0 °C from 0 mmHg to 800 mmHg.  In order, what changes occur?

• deposition, melting
• sublimation, melting
• condensation, freezing
• deposition, freezing

Based on this phase diagram, which state is the most dense?

• gas

• solid

• liquid

• solid and liquid have equal densities

Tags

NGSS.HS-PS1-3

Water will boil at temperatures above 100 °C at pressures __________ 760 mmHg.

• below
• above
• equal to
• significantly below

Which statement is true for carbon dioxide at -60 °C?

• All three phases are possible.
• It can exist as a solid or a gas, depending on pressure.
• It is a solid.
• With enough pressure it can be melted.

Based on its phase diagram, which is the most dense state for CO₂?

• gas
• liquid
• solid
• supercritical fluid

What is true regarding CO₂ for temperatures above 31 °C?

• It can never be liquified.
• It decomposes.
• It has a high pressure.
• It is a plasma.

At 10 atm, dry ice is heated from -100 °C to 30 °C.  What changes occur?

• freezing, then condensation
• melting only
• sublimation only
• melting, then boiling