Hot and Cold Packs & how Fast or Slow Can It Go Lab Reports attached are the chemistry lab reports. Please add the pre-lab questions from the first documen

Hot and Cold Packs & how Fast or Slow Can It Go Lab Reports attached are the chemistry lab reports. Please add the pre-lab questions from the first document to the rest of the questions on the other documents. Experiment 9
Designing Hot and Cold Packs:
A lesson on Exothermic and Endothermic Reactions
PURPOSE
Students will be able to…
• Determine the most effective chemical for use in a cold pack
• Determine the most effective chemical for use in a hot pack
• Design an effective hot pack or cold pack
• Describe the differences in exothermic and endothermic reactions based upon
the reactions they conducted in the lab
BACKGROUND
Cold packs are used to treat sprained ankles and similar injuries. A cold pack is
typically made of a thin plastic inner bag containing water. That bag, in turn, is
surrounded by a heavier plastic bag containing a solid substance. When the pack is
twisted, the inner bag breaks and releases the water. As the solid substance
dissolves in the water, energy is absorbed and the resulting mixture gets colder.
Some hot packs are similar in design; however, they are used to warm up the
body (or keep it warm), prevent hypothermia, and soothe sore muscles. One hot
pack of similar design requires you to empty the contents of a chemical pack into
the hot pack container and then simply add water. The reaction will then reach a
temperature of 160° F and will keep that heat for an hour and a half assuming the
individual is well insulated from the cold.
In this experiment, you will first determine temperature changes when several different
solid substances are dissolved in water. Using graphical methods, you will then
determine which substance you would choose in developing your own cold pack or hot
pack and explain why this would be the case. You will then create your own design for
the most effective cold or hot pack.
PRE-LAB
1. Write the sentence correctly: Energy is (released/required) to break a bond and
(released/required) when a bond forms.
2. Determine the following for both an exothermic and endothermic process:
a. What happens to the temperature of system?
b. What happens to the temperature of the surroundings?
3. Categorize a cold pack and hot pack as either exothermic or endothermic. Explain
your decisions.
4. How could you determine if a substance should be used for a hot or cold pack?
5. You will be asked to design a hot/cold pack in the A&D portion of the experiment.
What are two variables that you think are important for a hot pack to have?

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