Instant cold packs used to treat athletic injuries contain solid NH4NO3 and a po
ID: 798055 • Letter: I
Question
Instant cold packs used to treat athletic injuries contain solid NH4NO3 and a pouch of water. When the pack is squeezed, the pouch breaks and the solid dissolves, lowering the temperature because of the endothermic reaction.
NH4NO3(s) + H2O(l) --------> NH4NO3(aq) Change of heat = +25.7kj
What is the final temperature in a squeezed cold pack that contains 50.0 g of NH4NO3 dissolved in 125mL of water? Assume a specific heat of 4.18j(g.C) for the solution, and initial temperature of 25.0C, and no heat transfer between the cold pack and the environment. (SHOW ALL WORK)
Explanation / Answer
Q=mc(Ti-Tf),m=50gm + 125 gm =175 gm
all values are given just substitute them