Changes of State

Name ______Date ______Period ______

On the line at the left, write the term which best matches the description.

______1. Conversion of a solid directly into a gas

______2. Opposite of vaporization

______3. Temperature at which solid and liquid forms of a substance exist in equilibrium

______4. Conversion of a substance from one of the three physical states of matter to another

______5. Change of state from liquid to gas

______6. Pressure exerted by a constant number of gas molecules above a liquid or a solid

______7. Transformation of a gas directly into a solid

______8. Phase change from solid to liquid

9. Why do ice cubes shrink and become rounded if left in the freezer for a long time?

10. Six transitions are listed in the diagram below. Use arrow to connect each transition to its beginning state and its ending state.

Beginning State / Transition / Ending State
Gas / Melting / Solid
Freezing
Liquid / Condensation / Liquid
Boiling
Solid / Deposition / Gas
Sublimation

11. In the phase diagram, correctly label the x-axis and the triple point. Write the names of all six phase transitions in the spaces provided.

A ______

B. ______

C. ______

D. ______

E. ______

F. ______

12. Chemists distinguish between intermolecular and intramolecular forces. Explain the difference between these two types of forces.

13. Classify each of the following as intramolecular or intermolecular.

______a. hydrogen bonding in liquid water

______b. the O-H covalent bond in methanol, CH3OH

______c. the bonds that cause gaseous Cl2 to become a liquid when cooled

14. Fill in the boxes below with the correct state of matter.

15. Using the phase diagram above, answer the following questions:

a. What is the value of the critical pressure?

b. What is the value of the critical temperature?

c. What are the values of the temperature and pressure at the triple point?

d. If the pressure is 50atm and -75˚C, what state of matter is the substance?

e. If the substance is at 1atm and -78.5˚C, what state(s) of matter may be present?

f. If the substance is at 1atm and 50˚C, what state of matter is present?

g. If the substance is at -56.4˚C, and 73.0atm, what state of matter is present?

h. Estimate a temperature and pressure at which both a solid and a liquid would be present at the same time.