Question

Cold packs are used to treat minor injuries. Some cold packs contain NH4NO3(s) and a small packet of water at room temperature before activation. To activate this type of cold pack, the small packet must be broken to mix the water and NH4NO3(s). The temperature of this mixture decreases to approximately 2°C and remains at this temperature for 10 to 15 minutes.
State the direction of heat flow that occurs when the activated cold pack is applied to the body.
Identify both types of bonds in the NH4NO3(s).

Answer 1

These types of reactions are called endothermic reactions. This is when the system absorbs the heat from the surrounding. In this case, the system is the chemical reaction and the environment is the direct vicinity of the chemical reaction. You notice that the pack becomes cold because heat from the surrounding is being absorb. 

The bonds involved in this substance includes ionic bonding and polar covalent.