States of Matter
After completing this course the students will be able to understand the calories required to change the state of matter.

    What if you wanted to freeze to -0C a frozen dessert mix that was 95% water and at 27C? How many calories would it take to freeze a 100 grams?

    FACTS OF IMPORTANCE

  1. 95 grams of water are present in the mix to freeze.
  2. to lower the mixture to a liquid at 0C it would require the removal of one calorie per gram of water.
  3. to change one gram of water at 0C to one gram of ice at 0C it would require the removal of 80 calories.
  4. since solute concentration is not listed the affect of solute can not be factored into the equation.

    5. CALCULATIONS

    1 gram of water at 27C to 1 gram of ice at 0C would require the removal of:

    107 calories (27 + 80)

    There are 95 grams of water and so it would require the removal of 10165 calories.(95 times 107).

    OBSERVATIONS

    This small problem only dealt with 100 grams. This is only 3.33 ounces or a little over one serving. It would be unusual to make only one serving of ice cream. The closest we might come would be the automated self-serve ice cream machines. The removal of calories requires energy in some form. It should indicate to you why the process of freezing a product may be expensive.
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