Chemistry 11 - Phase Changes & Kinetic Energy

What is a chemical change?

When a new substance is formed

What is a physical change?

A change is phase, no new substance formed

What is melting and freezing temperature?

• The temperature a a solid changes to liquid and vice-versa.

• They are opposites and the same temperature.

What is boiling and condensation temperature?

• The temperature a liquid changes to a gas and vice versa.

• They are opposites and the same temperature.

Explain the phase change graph

What is happening in the plateaus of a temp/heat graph?

Bonds are breaking and phases are changing.

What are the 3 kinds of kinetic energy?

• rotational

• translational

• vibrational

What is rotational energy?

• molecules rotate around their x,y,z axes of rotation

• maintain their bond lengths and angles

What is vibrational energy?

• bonds within molecules stretch and shrink or adjust their angles (vibrations)

What is translational energy?

• molecules traveling in a straight line.

What is the kinetic energy at solid state?

• increasing amounts of vibrational and translational energy

• no rotational energy

What is the kinetic energy at melting point?

• bonds are breaking, allowing rotational energy

What is the kinetic energy at liquid state?

• increasing amounts of vibrational, translational and rotational energy

What is the kinetic energy at boiling point?

• the translational energy is high enough to break bonds restricting movement - can move more

What is the kinetic energy at gas state?

• increasing amounts of vibrational, rotational and translational energy.

What energy is the greatest and breaks bonds at every state?

Translational energy