When Holly injures her shoulder playing baseball, she uses an instant ice pack to reduce the swelling. She breaks the inner, activator portion of the instant cold pack releasing the solid urea into the surrounding water. What process does Holly observe as she uses the cold pack? A) Urea absorbs and releases heat energy into the surroundings. B) When the urea dissolves it absorbs heat and the cold pack gets colder. C) The urea causes the surroundings heat up as the cold pack releases energy. D) As the urea mixes in the water it releases heat making the cold pack colder.

B) When the urea dissolves it absorbs heat and the cold pack gets colder.

Explanation:

Cold packs usually contains two bags, one contains a water and the other inside is a form of ammonium nitrate  as the solid (s) or urea.

Breaking the inner portion activates the instant cold pack thereby releasing the solid urea into the surrounding water makes the urea to react with the water and makes it cold. This is because the reaction that takes place then undergoes an endothermic reaction, Hence heat is absorbed from the surroundings and the cold pack gets colder

a c d and f

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frequency, z, and the collision density, z, in carbon dioxide (co2), r 180 pm at 30 °c and 120 kpa