One type of cold pack uses ammonium nitrate dissolving in water to produce a cooling effect.
What does this suggest about the energetics of the process involved?
When solid sodium hydrogen carbonate is added to a solution of citric acid in water, a chemical reaction takes place. This reaction changes the temperature of the water, which may be measured with a thermometer as shown in the diagram.
If enough sodium hydrogen carbonate and citric acid are present, the change in temperature may convert the liquid water to a different state of matter.
Why does this reaction change the temperature of the water?
Which of the following is the best description for what happens when the reaction causes the liquid water to change state?