6. Phase Diagrams

PHASE DIAGRAMS

ESTEEMED STEM - CHEMISTRY

SY 2022 - 2023

LEARNING OBJECTICES

• Differentiate phase changes according to addition and removal of energy

• Describe the nature of the following phase changes in terms of energy change and the increase or decrease in molecular order: solid-liquid, liquid-vapor, and solid-vapor.

• Interpret the phase diagram of water and carbon dioxide

PHASE CHANGES

• It occurs when energy (usually in the form of heat) is added or removed from a substance.

• Phase changes are physical changes characterized by changes in molecular order.

• Molecules in the solid phase have the greatest molecular order, and those in the gas phase have the greatest randomness

Drag and Drop

SOLID TO LIQUID

Energy Change: ​​

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Molecular Order: ​

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Drag these tiles and drop them in the correct blank above

HEAT IS ADDED

DECREASES

HEAT IS REMOVED

INCREASES

Drag and Drop

LIQUID TO SOLID

Energy Change: ​​

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Molecular Order: ​

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Drag these tiles and drop them in the correct blank above

HEAT IS REMOVED

INCREASES

HEAT IS ADDED

DECREASES

Drag and Drop

LIQUID TO GAS

Energy Change: ​​

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Molecular Order: ​

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Drag these tiles and drop them in the correct blank above

HEAT IS ADDED

DECREASES

HEAT IS REMOVED

INCREASES

Drag and Drop

GAS TO LIQUID

Energy Change: ​​

Placeholder

Molecular Order: ​

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Drag these tiles and drop them in the correct blank above

HEAT IS REMOVED

INCREASES

HEAT IS ADDED

DECREASES

Drag and Drop

SOLID TO GAS

Energy Change: ​​

Placeholder

Molecular Order: ​

Placeholder

Drag these tiles and drop them in the correct blank above

HEAT IS ADDED

DECREASES

HEAT IS REMOVED

INCREASES

Drag and Drop

GAS TO SOLID

Energy Change: ​​

Placeholder

Molecular Order: ​

Placeholder

Drag these tiles and drop them in the correct blank above

HEAT IS REMOVED

INCREASES

HEAT IS ADDED

DECREASES

PHASE DIAGRAMS

•A phase diagram is a graph in which areas represent phases and curves represent equilibrium between phases.

•Each area represents a range of temperature and pressure at which each phase is stable

​PHASE

DIAGRAM

​PHASE DIAGRAM - CURVES

​• Melting/Freezing curve – the curve on a phase diagram which represents the transition between liquid and solid states 

• Vaporization/Condensation curve – the curve on a phase diagram which represents the transition between gaseous and liquid states 

• Sublimation/deposition curve – the curve on a phase diagram which represents the transition between gaseous and solid states 

​PHASE DIAGRAM - CURVES

​• Melting/Freezing curve – the curve on a phase diagram which represents the transition between liquid and solid states 

• Vaporization/Condensation curve – the curve on a phase diagram which represents the transition between gaseous and liquid states 

• Sublimation/deposition curve – the curve on a phase diagram which represents the transition between gaseous and solid states 

​PHASE DIAGRAM - CURVES

​• Melting/Freezing curve – the curve on a phase diagram which represents the transition between liquid and solid states 

• Vaporization/Condensation curve – the curve on a phase diagram which represents the transition between gaseous and liquid states 

• Sublimation/deposition curve – the curve on a phase diagram which represents the transition between gaseous and solid states 

​PHASE DIAGRAM - CURVES

​• Melting/Freezing curve – the curve on a phase diagram which represents the transition between liquid and solid states 

• Vaporization/Condensation curve – the curve on a phase diagram which represents the transition between gaseous and liquid states 

• Sublimation/deposition curve – the curve on a phase diagram which represents the transition between gaseous and solid states 

​PHASE DIAGRAM - POINTS

•Each point on a line the phase diagram represents a temperature and pressure at which the 2 phases on either side of the line coexist in equilibrium

•The triple point is the temperature and pressure at which all 3 phases of a substance coexist in equilibrium.  

•The liquid-gas curve ends at the critical point, where the liquid and gases become indistinguishable

​PHASE DIAGRAM - POINTS

•Each point on a line the phase diagram represents a temperature and pressure at which the 2 phases on either side of the line coexist in equilibrium

•The triple point is the temperature and pressure at which all 3 phases of a substance coexist in equilibrium.  

•The liquid-gas curve ends at the critical point, where the liquid and gases become indistinguishable

​PHASE DIAGRAM - WATER

For H₂O

• Normal boiling point

•(P = 1 atm & T = 100 degree Celsius or 373 K)

• Normal freezing point

•(P = 1 atm & T = 0 degree Celsius or 273 K)

​PHASE DIAGRAM - WATER

For H₂O

• Normal boiling point

• (P = 1 atm & T = 100 degree Celsius or 373 K)

• Normal freezing point

• (P = 1 atm & T = 0 degree Celsius or 273 K)

​PHASE DIAGRAM - CARBON DIOXIDE

For CO2

• Normal sublimation point

• (P = 1 atm and

T = -78.5 degree Celsius or 194 K)

• It directly goes from solid to gas, thus subliming

Hotspot

Refer to the phase diagram on the right. Determine the TRIPLE POINT

Hotspot

Refer to the phase diagram on the right. Determine the CRITICAL POINT

Hotspot

Refer to the phase diagram on the right. Determine the SOLID PHASE

Hotspot

Refer to the phase diagram on the right. Determine the GAS PHASE

Hotspot

Refer to the phase diagram on the right. Determine the LIQUID PHASE

Hotspot

Refer to the phase diagram on the right. Determine the NORMAL BOILING POINT

Hotspot

Refer to the phase diagram on the right. Determine the NORMAL FREEZING POINT

Hotspot

Refer to the phase diagram of CARBON DIOXIDE on the right. Determine the TRIPLE POINT

Hotspot

Refer to the phase diagram of CARBON DIOXIDE on the right. Determine the CRITICAL POINT

Hotspot

Refer to the phase diagram of CARBON DIOXIDE on the right. Determine the NORMAL SUBLIMATION POINT

Hotspot

Refer to the phase diagram of WATER on the right. Determine the TRIPLE POINT

Hotspot

Refer to the phase diagram of WATER on the right. Determine the CRITICAL POINT

Hotspot

Refer to the phase diagram of WATER on the right. Determine the NORMAL BOILING POINT

Hotspot

Refer to the phase diagram of WATER on the right. Determine the NORMAL FREEZING POINT

Thank you!