The Heating Curve for Water

INTRODUCTION:

What happens to a solid substance when it is heated?

In the absence of reactions that change the molecular structure of a compound, two types of behavior are possible when a compound is heated: The compound can simply get hotter (that is, its temperature increases) or a phase change can occur.

The transition from the solid phase to the liquid phase is an example of a phase change, which is often called melting. Boiling or vaporization is an example of a phase change from the liquid to the gas phase.

This exercise explores the changes that occur to a substance during heating. At the outset of the experiment, a beaker is filled with ice and placed on the hot plate. Because the beaker is exposed to the atmosphere it experiences a constant pressure at all times during the experiment.


PURPOSE:

In this experiment you will:
  1. heat a sample of ice/water to the boiling point while recording temperatures along the way.
  2. draw a heating curve that illustrate water's phase changes.
  3. make conclusions about the Kinetic Theory of Matter as related to phase changes.


EQUIPMENT:

calorimeter with lid
hot plate
ice
thermometer


INSTRUCTIONS:

  1. Each person in your lab group must read every page in this online procedure. Along the way, there will be questions that you must answer.
  2. Designate one person in your group as the Data Recorder. This person should open the Google document Experiment 11 - The Heating Curve for Water for the approved answer template.
  3. When this Google document opens, sign in to your Google account.
  4. From the FILE Menu, choose Make a copy...
  5. From the FILE Menu, choose Rename...and rename the document as follows: Exp 11 - Period (1, 3, 6, or 8) - Group #.
  6. Share this document with the members of your group and with Mr. Skubis at HSTChemistry@gmail.com.
  7. As a group, answer all questions. Remember to use complete sentences and be mindful of grammar, spelling, and punctuation.
  8. REMEMBER: **Plagiarism** is a form of **Academic Dishonesty** which carries harsh consequences. DO YOUR OWN WORK!


PROCEDURE:

Using the data table in the accompanying Google Doc, RECORD OBSERVATIONS and/or DATA for each procedure step.

  1. Fill a calorimeter with ice. Add just enough tap water to cover the ice.
  2. Plug in the hot plate and set its heat dial to 10.
  3. Place the calorimeter with ice on the hot plate.
  4. Suspend a thermometer as deep in the ice water as possible without the bulb touching the bottom or sides.
  5. Record the beginning temperature of the ice water.
  6. Read and record the temperature after each minute.
  7. When the water is above 90┬░C and has been boiling for 5 minutes, you may stop recording and shut off the hot plate.
  8. Remove the calorimeter and water from the hot plate and allow to cool in place.