Final answer:
Cold-pack containers should minimize heat gain from the environment, which can be achieved by using insulating materials, such as foam-walled drink cups or take-out trays.
Step-by-step explanation:
Chemical cold packs, such as those used for treating injuries, are designed to absorb heat through an endothermic reaction that occurs when certain chemicals are mixed. These packs generally contain compartments with substances like ammonium nitrate and water that are kept separate.
When the pack is activated by squeezing, the inner seal breaks, allowing the ammonium nitrate to dissolve in the water. The dissolution of ammonium nitrate is associated with a significant absorption of heat (ΔH soln = 25.7 kJ/mol), which results in the cooling effect of the pack.
Cold pack tenders or users should look for containers that minimize heat gain from the environment to preserve the coldness of the pack. This can be achieved by using containers with greater thickness, smaller surface areas, and those placed in environments with a lower ambient temperature.
While the specific containers for cold pack storage are not detailed in the information provided, commonly used insulating materials in packaging, such as foam-walled drink cups or take-out trays, could be examples of containers that could help maintain the cold temperature of an activated pack before use.