As substances change from one state to another, a lot is going on from a molecular perspective. Today we get to learn more about this.

Warm Up

  • 1. Sketch an image of the molecules in the beaker before the heating.
  • 2. Describe what happens to the ice molecules as heating begins.
  • 3. What happens to the temperature once the ice begins melting?
  • 4. What happens to the temperature once the ice is completely melted?
  • 5. Describe what happens to the liquid water molecules at this point.
  • 6. As we continue heating, we see that the temperature becomes relatively constant once boiling begins.  What temperature does this occur at?
  • 7. Describe what happens to the liquid water molecules at this point.

Objectives

  • Use enthalpy to convert between energy and grams
  • Describe molecular changes during phase changes
  • Calculate energy absorbed or released during heating/cooling through phase changes

Homework

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